I was riding my Raptor back from Red Obesilik to base , then on first island in route it spawned there.That was so massive 5 times the bronto.Myths say it true ,it can make any island deserted in few minutes.I saw it walking and crushing all the tree in the way.Its health was 230k , can't remember the lvl.It was calm not hitting anyone unnecessary.I ride beside it with my Raptor, didn't even noticed it.
Of course, I got on a PVP server, and I always find these guys. I decided to punch it. I thought it was passive. Nope nope nope and NOPE. It will squish you and as the life is crushed out of you, you realize you’re still a noob.
Easily killable with a wyvern. Lightning and poison easiest down to longer range in attack. Just hover above and light it up :) killed my first today and it didn't touch me once. Just remember to watch stamina ;)