Based on the replies you've gotten so far I suspect this may be a joke I'm not getting, but I'm choosing to react as if it's a genuine question anyway.

A coelacanth is a super old fish that everyone thought was extinct, and then one day we just happened to find them alive! They're a "living fossil" animal in that they haven't changed much in a very long time and give us a window into the past. Here's a picture I stole: