they are giants of the deep that have been hidden for centuries from our eyes. only surfacing very rarely every a few milennias to mate, away from the comforting heat of the deep sea thermal vents.
but this time, as they had risen. something's different. the earth is no longer covered in ice. in fact, it seems to be melting, and getting warmer.
more and more start to surface across the globe. they only have one priority in their mind. to breed as many of themselves as possible and fill this new, warmer earth with their kind