My daughter's third birthday brought a shower of extremely good presents into our home because, after years of my friends and family knowing and loving her, she can finally actually "do things." She's mastered basic motor skills, can speak and walk, and sort of function as a very small person. She's more fun than a baby. Along with the tie-dye t-shirt kit, the bird costume, the paint by numbers, and the puzzles, Zelda got what I immediately thought was the greatest present ever.

"Triassic Triops! From the age of the dinosaurs! They're alive!" the box screamed. Inside the box was a vast array of items: a packet of eggs, three packets labeled "Triops baby food," "Adult Triops food," and, vaguely, "Triops food." There was also a little plastic dropper, a small plastic aquarium. "We are in for a treat!" I declared to my daughter at the kitchen counter as she frantically dragged a chair over to me while I pulled out the instructions.

Our nightmare was only beginning.

"Okay, there, not so fast," I said. "Looks like we need spring water. We don't have any." My husband, Josh, said, "This looks very complicated," as he put on his coat to head to the store for a gallon of spring water. "This says NOT distilled! Has to be spring," I yelled after him, saying to my daughter, "Very soon."

But it wasn't very soon, it turned out. The next step said that the water had to be "aged" for 24 hours minimum by adding three limestones per liter to the jug. "There aren't any limestones…" I muttered, looking through the box. There were. I found them. We added them to the water dutifully, and I told my 3-year-old that she had to wait "until tomorrow."

By "tomorrow," she had sort of forgotten the triops. But I had not. I poured the aged water into the aquarium and then read on. There was also a small packet of sand that must be added to the water. I added it to the water. I waited until my kid came home from school to add the eggs to the water. It was extremely anti-climactic. "In just…," I read the next step of instructions, "five to seven days, we will have creatures!" I read on, deflating at the instructions to "keep them warm under a lamp during the day" and to "cover their tank in foil at night" so they knew to rest but stayed warm.

Over the next series of days, I went through the steps of feeding the seemingly empty tank the correct foods at appointed times, and one morning when we woke up, there in the tank were five… no six, yes six! Tiny little things, barely visible, they looked like, well, sperm sort of, just shooting around in the tank. Within a day or two, they had doubled in size. Zelda took to calling them "my worms."

"I need to feed my worms," she said some days when we returned home. The worms liked eating their pellets, but the instructions also suggested we buy them blood worms, which we just happened to have a little container of because we also have a fish, Duckie. The instructions also suggested we grate carrots or cauliflower really small and give that to the triops too. They doubled in size every few days, and that's when I realized why they were called real live dinosaurs.

They doubled in size every few days, and that's when I realized why they were called real live dinosaurs.

Triops are prehistoric animals. They're freshwater crustacea that have survived through the millenia. Little shrimp basically, except uglier. They have three eyes. Literally. They were here long before people, and they live on every continent in the wild to this day. They'll probably be here long after we're gone, except in Britain, where they are weirdly considered endangered. Boxed triops for children, like sea monkeys, are made in a lab, and their eggs have the interesting ability to exist, dried up, for years, just waiting for someone to add limestone-aged spring water to them so they can hatch. I do not know their lifespan. I cringe to even think about Googling for that information. Because the triops are kind of a huge pain in my ass these days. The worms aren't really Zelda's: They're mine.

They look like horseshoe crabs. They eat twice a day. They like light but not too much light. They want to be warm. It's winter in New York, and my house is often cold at night. The triops, like my daughter, my husband (to a lesser extent, but I'd feel bad leaving him off the list), our dog, Penny, the betta fish, Duckie, are just another in the list of beings dependent upon me for life and happiness. The dog takes medication every day and is on a special diet. Duckie is a pain in her own way: Her water needs to be painstakingly cleaned after I net her little ass into a different container once a week. But the triops? They're disgusting. Their water routinely needs to be changed every three days or else it stinks and is dark brown. I worry about them all the time. I'm a vegetarian, I care about all living things, I can't starve them or neglect them. I must do my best to keep them alive.

The worms aren't really Zelda's: They're mine.

This box of triops, purchased by my sister-in-law, Katie, at the Museum of Natural History for my daughter, Zelda, is the worst present to have ever crossed the threshold of my home. Two weeks ago, it was so cold in the den where they live that I took them into my bedroom to sleep one night. In the morning, before my daughter was awake, I carried their little box back to the den, cranked up the thermostat, turned on the lamps, and went to feed my six little motherfuckers their grated carrot and ration of early-morning pellets.

But there weren't six of them anymore. There were three.

This couldn't be right: There were six just last night. There have always been six triops. I tapped the plastic to move the water — a little cloudy, could use a new half gal of limestone-aged spring water, I thought to myself — and see if they were hiding. But they freak out when I feed them, and there were certainly only three in the container. No corpses floating in the water or lying on the bottom of the tank.

I texted my husband.

"The worst thing in the world," I wrote. "There are only three triops now. There were definitely six last night."

"NO." was the only response.

There are upsides to the triops, I won't lie: They are cool. I'm sort of attached to them. I'll miss them when the rest of them disappear, I bet.

We still have three triops. I just fed them a grated spear of broccoli 10 minutes ago. The water is cloudy. I'm aging new water on the kitchen counter right now. The others have never been seen or heard from again.