This therizinosaurus is easy to kill if you have a strong bow and you need to stay away from it because it deals so much damage it is hostile if you came very close to them.In my solo island i killed 4 therizinosaurus with no armor and just a bow make sure you a high attack damage and bring some huge companions like diplodocus.I you spot some therizinosaurus you can eother kill it for some good loot or run away.