In David’s previous life, he was a mad scientist. According to him, I was a lab rat. I’m chopping the remaining half of a watermelon and am more concerned about the ant infestation I had eliminated yesterday because I forgot to clean the juice-soaked cutting board. I remind myself to wash the cutting board after I’m done and to spray the crown moldings with a mixture of white vinegar, detergent, and leftover shower water I’d collected because of the water restriction mandates.

“Want any watermelon?” I ask as I place several chunks on a plate and stab the largest with a fork. I extend my arm across the counter, holding the fork in front of David’s face. He takes the fork and eats the chunk in one bite.

“I’m serious,” he insists. “You were an albino rat with creepy red eyes.”

I pull a napkin out of our old take-out box from Haidilao and wipe the red juice dribbling down his chin. “And what was I doing?” I’d never worked with lab rats before. I dodged the biomedical track because I didn’t want to suffer through an eternity of school, much to the disappointment of my parents who used to run experiments with electrodes stuck in rats’ heads. David wants to be a doctor when he grows up although I caution him that I might not be able to afford his entire medical school bill. He tells me he’ll get an MD-PhD, also known as the doctor-doctor, and I won’t have to pay a cent.

“You were part of an empathy study, the rat that got to roam freely while the other was restrained in a clear tube at the center of the cage.”

“Did I free the trapped rat?” I walk toward the sink to rinse my hands, then turn back toward the cutting board and begin to cut the watermelon rinds away from the peels. The rinds taste good pickled or as light sweeteners in soup. The juice sticks to my fingers but I’m trying to save water and only want to wash my hands once, after I’m done chopping, so I deal with it.

“Always,” David replies. “Even when we put chocolates in another tube, you’d free the trapped rat at no statistically significant higher rate than without the chocolates.” David never sounds like a twelve-year-old and I’m used to it. I address him like I would my old classmates who toiled through medical school while I dropped out and sold my soul to corporate America. I used to ask David whether he’d like cash to buy food from the cafeteria or a paper bag packed with an Uncrustables from the freezer, and then I learned he had been buying lunch with money he’d earned from building websites for people. He’d sneak the cash I gave him back into my purse. I stopped trying to give him the normal things kids would want. He doesn’t ask for anything. I buy him good food and new clothing, which he’ll eat and wear without comment—not when I oversalted the rice noodles and left bits of eggshell in the chawanmushi, nor when I accidentally bought him girls’ sweatpants. I let him drive most of our conversations because I never know if my questions are pointless, although sometimes I can’t stay quiet.

“Other animals feeling empathy—is that supposed to be surprising?” I ask.

“It’s not about the surprise. It’s about providing reasonable evidence that rats empathize. Don’t look at the hypothesis as something with emotional or philosophical value.” David loves to lecture although he doesn’t realize he’s lecturing; otherwise, he’d probably clam up because he can’t stand teachers “preaching at him.” He hates when they expect him to “spongify,” which he describes as absorbing words until they leak out of your ears, leaving only the grimy bits. I’m okay with him preaching at me. It’s better than silence.

I nod. “Did you finish your homework?” I can’t break the small talk habit. The question provides me with an illusion of proper parenting.

David nods, but he isn’t paying attention when he replies, instead maneuvering one of the white seeds from the watermelon and attempting to drive a fork prong through the seed’s center. “Carl says if you eat the black seeds, they’ll grow watermelons in your stomach.” Carl is David’s only friend, although I don’t know how they became friends. Carl is a wiry guy, so much shorter than the other twelve-year-olds that he blends in with the elementary school kids. He always has detention or wrestling practice and will ride the late bus home with David, who stays late because I don’t get back from work until five and he doesn’t want to be home alone.

“That’s silly.” I laugh, remembering all the black watermelon seeds I had accidentally swallowed as a child.

“Right?” David says, and for a moment, it’s like we’re on the same wavelength.

Later, I look up rat empathy studies while waiting for work files to download. If we’re biologically programmed to want to help others, are nice people extra-evolved? Some form of genetically optimized altruistic specimen? One of the papers mentions how empathy in motherhood might make females more likely to open the door than males. I rub my eyes and debate between getting up to turn the light brighter and continuing to sit and attempt to make sense of rats and chocolate and motherhood and doors.

David and Carl are playing in the backyard as they always do on weekends. By play, I mean David is digging up earthworms and trailing ants into his assortment of homemade “control environments” made from plastic wrap, rubber bands, and empty pork floss containers, and Carl runs around, head and shoulders hunched toward the ground instead of looking forward (no wonder he’s always scratched up), pointing and shouting at another bug he’s spotted. “Moth!” Carl shouts. “Caterpillar! Spider! Roly-poly!” David hands Carl a piece of chalk to mark the locations so David can loop back to investigate these other alien forms of life.

They seem like energetic, playful kids from my office. If I squint from my office window, I might see David separating pill bugs into dry and damp jars, drying half of them out until they roll into balls to preserve moisture on their gills. Last week, he told me he was looking for evidence that they emerged from the sea to conquer land but they still had several evolutionary iterations to go through because dry places turn their gills into a source of suffocation.

David stands and brushes his hands together, careful not to get dirt on his clothing. He never trails grime into the house, leaving and returning like a ghost. There’s not much left for me to clean besides washing dishes and wiping dust off old hanzi handwriting contest trophies and soup spilled over my keyboard. David stretches his shoulders and elbows and crouches down again, diligently prodding at the earth.

I open the window and call them in for snacks. Carl dashes in as soon as he hears my voice. I yell twice more for David to peel himself away from the ground and come into the house. I prepare a bowl of grapes and take out the box of milk tea popsicles from the freezer. Carl snatches one of the popsicles, ripping away the wrapper with sticky fingers, licking the brown sugar milk stuck to the inside of the plastic casing before tossing it on the counter. David picks up the wrapper and drops it in the trash. Then he plucks a grape from the bowl and rolls it between his fingers before swallowing it. I give the second popsicle to Carl as well. I know they’re too sweet for David, but I want him to have options. Carl will eat anything David doesn’t want so I don’t worry about leftovers.

“Make any progress?” I ask.

“Not really,” David replies.

I turn to Carl who’s focused on licking the frozen cream to get to the syrupy boba at the center. “Did you know I was a lab rat in my previous life?”

Carl shakes his head.

David frowns. “Why are you telling others?”

“Maybe they were the rats I rescued,” I joke even though David rarely understands jokes. “It’s fate.”

“No, the other rats were just rats. The other lab assistants were just lab assistants. Only we were reincarnated. Just us.” David nods, as though he’s trying to persuade himself. The gesture is contagious. I nod too.

“Okay. Just us.” I pat David’s head. His hair feels like sharp blades of grass under my fingers, and I like when the tips get caught under my fingernails and brush across.

Carl is nearly done with his first popsicle. I wonder if Carl understands words like “reincarnation” or concepts like “previous lives” or how lab rats are used. Is this common knowledge for kids? Have they already developed a moral code that puts them at crossroads with experimenting on animals and verifying product safety before testing on humans? I think David has already gotten over the moral dilemma, and by that I mean he realizes there’s no real answer, so the next best thing is to distract yourself with quantifiable things. Like how quickly a rat will open the cage to allow the adjacent drowning rat to reach land. Or how evolutionary habits influence survival based on precise biochemical development. Carl unwraps the second popsicle as David brings another grape to his mouth. Before plopping it in, David brings his hand back down to the table, pauses, and holds it toward me, an offering. I shake my head. “You two have your fill first.”

In the evening, after Carl has left and I’ve finished washing the dishes and David has showered, I stop by his bedroom to tell him good night. It’s the least I can do, since anything I can read out loud to him, he can read by himself, and faster. Sometimes we’ll hold hands and talk about how the world works—about health insurance and deductibles, how time in the market beats timing the market, how wire transfers are different from direct deposits—but I think we’re running out of topics for which I can provide an intellectually stimulating discussion partner, so I’ve gotten accustomed to knocking on his door and cracking it open if the night-light is still on, and whispering, “Good night,” before shutting the door again. David prefers the door shut. He claims my footsteps quake through the house. I wonder if he can also hear the critters scuttering in the attic, underneath the floorboards, in the closets muffled by cardboard boxes.

I’m not sure where the mice are coming from given David always cleans up after himself and puts his food away. I like to think it isn’t me who is negligent, although I’m the one who takes a plateful of chow mein clusters into the study room, crunching through the dried noodles and peanuts and chocolate at my desk. I buy several glue traps from The Home Depot because I’m scared of the snapping traps whose jaws are armed with two rows of teeth to clamp down and destroy mouse heads—or my fingers, if I’m not careful. I set one trap in the pantry behind the sacks of rice and sugar, one in the study next to the filing cabinet with all of David’s certificates and awards, one at the foot of the grand piano David abandoned after growing bored of classical music, one between the pots of succulents I regularly forget to water so David waters them for me.

It takes me a week to notice the traps are all gone.

“I’m repenting,” David explains when I find them stacked in his drawer.

“These are mice, not lab rats,” I say. “Even if they were rats, I don’t feel any resentment from being subjected to experiments. No hard feelings for past lives.”

David silently stares at the traps for a moment, and then leaves the room. I wait to hear the door slam shut, but all I hear is the creaking of floorboards and the fading rhythm of his footsteps as he makes his way to the backyard. He likes to spend time outdoors and says it’s less stifling, less controlled. I wait for him to run back screaming and crying, although he never does. I’m not sure why I’m waiting. I should know better.

In the end, I don’t set up more traps and leave them in David’s drawer. The scratching and scattering fade too, and I realize from the very beginning, I’ve never seen any mice.

David wants to dispose the traps directly into the public dumpster rather than in our trash can. I ask him to take out the compost while he’s at it. He stuffs the traps in the trash bag and heaves it out of the can. With his free hand, he grabs the small bag of banana peels and chicken bones and leaves through the garage. Even though I haven’t asked him to do so, he attempts to wheel the overflowing blue recycling bin along too, his figure dwarfed by garbage and collapsed cardboard boxes. I catch up to him, my strides still longer than his—a fact I often forget—and take the bin from his grip. “That’s too much for you.”

“No, it’s not,” he insists.

I grab the recycling bin from him. “Your body hasn’t caught up to your brain yet.” He’s slightly shorter than my chin. We walk over to the dumpster together. There’s one compost bin, but the recycling is divided into paper, metal, and glass. I begin separating the junk mail from the tomato sauce cans from the empty Guilin chili sauce glass jars. “You want to toss?” I ask David. He nods and picks up the Safeway coupon book and sends it spinning like a frisbee into the paper bin. “Nice!” I give him a high five. He touches my palm like he’s afraid of sending me flying. His finger pads skim my calluses and instead of hearing the crackle of palms hitting each other, I hear the jars clank as David gathers several in his arms and walks toward the glass-designated bin. He refuses to throw those in. “It’s too loud,” he reasons, even though I know how much self-restraint it takes not to attempt a goal. “You don’t like the noises.” He’s right: I hate loud noises more than I hate chewing sounds or uneven clock ticks that keep me up at night. I mistakenly complained to him while we were at my parents’ golden marriage celebration: their guests were guffawing about how they thought IKEA was a luxury brand when they first visited the West, and I sat next to David, jumping in my seat every time they roared in laughter.

I might’ve winced from the sound of cans and metal hitting each other because he reassures me as he carefully places one jar at a time in the bin, “Don’t worry, it’s understandable. Noise can make you claustrophobic. You’re subconsciously recalling your previous experiences in cages that scientists would tap and lift arbitrarily.” Maybe it’s true. I also dislike being strapped into a car even though I know the seatbelt is meant to save my life.

After we head back in, David asks me to pour him a mug full of strawberry CALPICO. The bottle is on the top shelf of the fridge, too high for him to reach. I pull it out of the side compartment and fill his cup, watching it glug-glug out, barely splashing the counter. “Do you want a boba popsicle too?” I ask, opening the freezer. David doesn’t eat them when Carl is here, but when it’s just the two of us, he’ll indulge on occasion even though he says he doesn’t like sweets. “They’re going to expire soon,” I lie. They expire in four months. David extends his arm, palm facing up, and I walk over to where he’s sitting at the table and place a cold bar in his grasp. Then I set the mug next to his book. He licks the creamy milk tea as he pages through his current book phase of the week: an ornithology guide. I catch glimpses of him as I wipe the counter and scrape off a few dishes. He’s not smiling, but his brows are relaxed and his back slumped. I’ve come to associate this demeanor with David’s state of contentment.

On Thursday evening, David arrives home from school with bruises on his forearms. I only notice when he reaches over at the dinner table, trying to grab a piece of celtuce drenched in cornstarch slurry. His sleeve falls to his elbow, and I see a chunk of his skin discolored to purple and red. I don’t want to pry because David prefers to deal with “personal” issues alone. He calls himself “solution-oriented.” I ladle him a bowl of pork trotter soup I boiled for eight hours to make tonkotsu ramen only to realize we have no more alkaline noodles.

“How did you get those bruises?” It’s taken me five minutes to muster the courage to ask. When I pass the bowl to him, I stare at his arms again, now almost entirely covered by sleeves except for a splotch of dark skin blending with the shadow of his cuff. Maybe my eyes are playing tricks on me. I’ve always been bad at catching those subtle shade differences. I suppose I got that from my past life David often mentions. Rats can’t detect color contrasts very well. They live in a blurry world but make up for their lack of depth perception with their large field of vision, which is wasted on now-human me since I’m not very interested in seeing more than I need to, although David likes to know what’s going on everywhere because science requires “making big connections” and that’s what ultrafocused PhD students miss out on. David tells me he got a PhD in his previous life.

“Grant pushed me into one of the playground posts,” he says before raising the soup bowl to his lips. I try to make eye contact with him, but after he sets the bowl down on the table, he begins to shovel rice into his mouth.

I haven’t met Grant, but I’ve met Grant’s mom. She was the lady who dressed in a black pencil skirt and some variation of a crimson blouse for every back-to-school event where she’d pick at the teachers’ grading policies: either they weren’t holistic enough or they put too much emphasis on unquantifiable soft skills like participation and discussion. She’d also complain about classrooms located too far from each other and how students would never make it to their classes on time if they needed to use the restroom. I had one direct encounter with her when we were seated in the homeroom classroom. Grant’s and David’s desks were next to each other, and I marveled at how small the chairs were. She asked me why David was bullying Grant and I answered, “No idea.” She stared at me like I was a cockroach and said, “David always diminishes the accomplishments of his peers. Arrogant people like him will get what’s coming to them.” I wondered if she’d look at me differently if I told her I was a rat in my past life, not a cockroach.

“Did you push Grant back?” I ask.

“That’d just escalate the situation.” David proceeds to lecture me on how you need empathy in these sorts of encounters. According to him, Grant struggles with math and has helicopter parents.

“I have plenty of empathy.”

David rises to put the dishes in the sink.

“Plus, empathy never saved me when I was a rat,” I continue.

David pauses, shutting off the faucet. “What are you talking about? You didn’t need saving. You saved the other rats.”

“That’s irrelevant to whether you can act in self-defense. Unless you think Grant had a good reason for pushing you.”

“Unforeseeable acts of aggression normally stem from evolutionary factors, or adversarial previous lives—perhaps Grant was a government agent unwilling to fund my lab’s research.”

“Were you trying to play cat and mouse with them again even though they didn’t invite you?”

“They say school is an all-inclusive environment. No straggler left to drown.”

“That is, certainly, a reality. Not ours, I think. Couldn’t you have played with Carl?”

“Carl doesn’t like games with winners and losers. And he thinks Grant might kill us with gator balls if we provoke him too much. Self-preservation at its finest,” David says, wincing as he balances a fish bone on his chopsticks, his bruised wrist quaking slightly above the compost bin next to the sink.

We clean the kitchen without speaking. I rinse a rag in a bucket of diluted dish detergent and hand it to David to wipe the table and white countertops stained with coffee marks and soy sauce. As I attempt to scrub burn marks off the wok without damaging the nonstick coating, I look at his back and thin arms, at how he pushes the rag across the surface like he’s trying to move a mountain. His sleeve rides up and down his arm as he moves, barely reaching his wrist even when unstretched. Even his pants end exactly at his ankles when he stands upright and rise to his lower calves when he bends over. David insists I don’t need to buy him new clothing since there’s no use wasting money during a growth spurt. Still, once every few months, I’ll replace his black sweatpants with a larger size and gradually, David has come to only wear that pair of pants. I’m sure he has noticed they are getting replaced. I make a mental note to shop for a new pair as he scrubs and reaches his arms across the table; they only make it two-thirds of the way over, even as he stretches his fingertips toward the other edge. I look down and realize I’ve been using the scouring side of the sponge to clean the wok.

After I’ve replaced the inner garbage bag with a fresh grocery bag, I pull an ice pack from the freezer and wrap it in a paper towel. There’s a dent in the middle of the ice pack, a result of dropping it while trying to fish out the frozen shaobing buried behind bags of separated and unidentifiable meat. I bang the ice pack against the counter, trying to soften and reshape it. Instead, the sharp edges of the counter rip through the paper towel and plastic casing of the ice pack. I imagine dropping the ice pack on the ground and retreating to my study.

“Come here,” I tell David, pointing to a chair next to the dining table.

He sits, accidentally banging his arm against the table’s edge. He flinches and his eyes water.

I remummify the dented ice pack and hold it to his bruise, stroking his head with my free hand. When his sniffling abates, I whisper that it’s okay.

LUCY ZHANG writes, codes, and watches anime. Her work has appeared in Salt Hill, The Pinch, The Baltimore Review, Southern Humanities Review, and elsewhere. She is the author of the chapbooks Hollowed (Thirty West Publishing, 2022) and Absorption (Harbor Review, 2022). Find her on Twitter @Dango_Ramen.