I’ve been playing ARK Mobile for a while, and I’ve learned that these guys biotoxin is pretty legendary. it is 100% needed in order to tame any high level creatures. simple way to kill them is pure them near the shore, and use a bow or gun to finish them off. occasionally they do happen to float ashore and die almost instantaneously, but that sometimes happens. but honestly, I promise, what they drop is legendary and you need it to get good tames e.i. Giga, griffin, quetzal
How to kill
Step one:get into the water and have them agro on you but stay close to shore so they can’t get you.
Step two: when they are almost on the shore and can’t go any further.
Step 3: kill them with any spear like weapon.