Never thought about fossil critters that way before.
I had two fossil trilobites on the coffee table once. Bought them in a curiosity shop in Provincetown. Imagine a pair of overgrown wood lice the size of hamsters, but made of sandy stone.
Keeping live ones as pets in a fish tank might have been cool.
Even better would be to have one of those dragonflies with a two foot wingspan from the Carboniferious Epoch.
It could perch on your shoulder while you take in on walks.