When they copy something they have a blue footstep effect and have weird animations when in water. They can only be picked up by things that can pick up what they are copying. On abb the actual enigmasaur can be picked up by a karkinos. Havent tried anything else
Enigmasaur
The Enigmasaur is a mysterious shapeshifter from Fantastic Tames: Season 1 that stores the forms of creatures it observes and transforms into them at will, gaining their unique abilities. It keeps useful traits as it changes shape, letting survivors combine powers and adapt to almost any challenge.

More Enigmasaur Encountering Tips
Lots of times you will come across them when they are already transformed. The transformed creature "emits" a blue like dust with footsteps and animations look just a little different. Like water physics seem off and other things like that. They are a neutral creature…
Lots of times you will come across them when they are already transformed. The transformed creature "emits" a blue like dust with footsteps and animations look just a little different. Like water physics seem off and other things like that. They are a neutral creature and when transformed as a hostile creature they will still remain neutral. Passive creatures that run away when too close like an equus will also not run away from you.
Hopefully his tail unravels all the way.
So we have big lizards with long tails
Its a 50/50 that its passive or neutral