On mobile, they only exist in aberration if you want proof check if you can unlock its Ingram :(
Karkinos
The Karkinos is a massive crab-like creature in Ark: Aberration that can grab and smash creatures and players. It can also throw them at great lengths. Using its strong legs, the Karkinos can leap to impressive heights.
How to survive, fight, and kill a wild Karkinos, from players who have done it.
I was floating above water in Crystal isles. I was close enough that if it jumped it could touch me but it didn’t attack me. I think they can only attack in water.