1. When I was five years old, my mother left for Europa as part of the expedition that discovered the Europan Pseudocephalopods, which have a superficial resemblance to squid. My mother wanted to call them Icypods but was overruled. Now I’m standing in front of a tank of live Icypod specimens, the very creatures that may have killed her. I’m going to finish her work. But I’m not going to let my work take over my life. I will be home every night to spend time with my husband and daughter.

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5. Even with Europa’s low gravity, the ocean under seven kilometers of ice is under tremendous pressure, equivalent to 900 meters in Earth’s oceans, so we store our Icypod school in a large hyperbaric chamber. The specimens explode when brought into the air, and the sulfurous smell of rotten eggs evacuates the lab. Kayleigh laughs when I tell her the story at dinner, but I don’t burden her with my next thought. Cameron holds me when I wake from a nightmare—my mother smelling sulfur when her submersible cracked and the cold Europan ocean rushed in.

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17. Each tentacle has a series of eyes. What use do they have for eyes? No sunlight penetrates the seven kilometers of ice, and Icypods are not bioluminescent. Perhaps other creatures beneath the Europan ice are. Or maybe the Icypods dive down to the glowing volcanic vents at the Europan sea floor. At dinner, Kayleigh says she remembers catching fireflies last summer, when she was three.

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37. The eyes are also ears. Sound waves passing through the eye generate electric signals.

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82. I have lost a lot of time staring into these eyes, watching them stare back at me like they knew me. Will Cameron or Kayleigh have the same reaction?

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131. Icypods gain tentacles as they age at a seemingly irregular rate.

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156. When a specimen is returned to the main tank after being separated and trained, they play and snack on each other’s tentacles. An Icypod can successfully swim through a maze it has never seen before if it has eaten the flesh of one that has been trained in that maze. They grab any novel item placed into their tanks. Could they be trying to eat these as a way to learn about them? I put a lot of toys in my mouth when my mother was on her mission. Eating things may be a way to learn for us too. I cracked a toy submersible in my mouth and I was convinced for a long time that caused my mother to sink to the Europan depths. Kayleigh outgrew mouthing her toys before she was three, for which I am grateful.

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187. We roast marshmallows outside after dinner. I think Icypod eyes are for the volcanoes. If memories are stored in their limbs, that would be a shared trait throughout the ecosystem, like brain stems in Chordata. If they learn via cannibalism, they might also gain the memories of the other species they eat. Cooking would break down the memory proteins, and they could eat their food without experiencing their prey’s death. They may even use tools to hold the food in the hot water above the smoking volcanoes.

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241. It took me several weeks to get superheated water into a tank at a hundred atmospheres of pressure. The specimens are drawn to the mock-volcanic vent, but don’t seem to want to cook their food, even after I provided them with skewers to hold the smelly tube worms we feed them. But the tube worm meat does not contain the memories of their death from explosive decompression.

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244. Europan metabolisms are ultimately based on sulfur from the volcanic vents. Icypods taste as terrible as they smell. I won’t be bringing one home for a calamari dinner.

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245. I know a few things for certain now. One: We need to send our Icypod specimens back to Europa so they can live free again. I need to be on the expedition there. I’m sure Cameron and Kayleigh will understand. Two: My mother loved me.