What on EARTH was this doing under my stand

So.. Yeah. Crayfish under the tank. Never bought a crayfish for the tank. I think the best explanation to this is my cat somehow managed to sneak this guy into the house one night, batted him around until he ended up under the stand, where he ultimately dried out/succumbed to injury. Another (unlikely) possibility is it just crawled in through the cat door. Anyone have any similar stories? 😭