The Gravicosta is a prehistoric ancestor to Gravitelamo family and possibly the entirety of aquatic tf2nimals.They have a large shell like heavy turtles but grow to the size of heavy whales. They are said to have jaws so strong that they ate the bones and shell of other tf2nimals of it's time period.
They where first discovered by Giovanni Pierrot and Sergeant "Major" William in the aurora area of the server, where Sergeant Major found a rock and, after some cleaning and chipping away at depris, they found a shell of of what may be a a baby Gravitcosta. Surprisingly it was the size of both of Sergeant Major's fists. Plans to revive it will be soon in the next week or sometime today