When the tusoteuthis grabs you you can avoid its attacks by firing an arrow at its beak during the attack

They are easier to find while riding a raft, having a monkey on your shoulder, and having a beard. It is recommended to have a big raft that looks like a pirate ship. The ship must have cannons.

When you see one of these, be ready to die.

Be extra careful around them, when exploring the sea caves, as they can grapple your dino (even your mosasaurus).