For some reason I was swimming with my lvl 1024 spino (Razorback), and I spotted some jellyfish. Razorback swam up to them after I got off to kill a icthiosaurus because I had him on agro. He started attacking them, and I instantly knew he was done for. But then they just died! He was swimming basically on top of them and hitting them! He didn't die! I was very confuzelled.