I saw this thing roaming around my camp in singleplayer once (in a area near where the southern coast and the southern jungle meet) and decided to approach it, BIG MISTAKE! It attacks you, and I suggest if you ever do what I did , you have a medium amount of stamina to run, because I was running away from the Therizinosaurus and it hit me while I was running. Best thing to do is build a spiked wooden wall and wait for it to die.
If you find this thing RUN it took me out in two hits and completely demolished my home and murdered my raptor and my little otter cuddles please like to pay respects to my little cuddles kept me warm on the cold nights
When I was a noob I approached one of these to read the name and look it up. I approached very, very slowly to judge whether it was hostile or not. When I reached it, I was surprised, but glad that it wasn’t going to attack me. Just as I got close enough to read the name, I’m suddenly thrown back. I close the app and use the app preview thing to read the name, then look it up. I haven’t stopped kicking myself for walking up to one of the strongest hostiles in the game