These bad boys are hard to tame so here’s my steps: Step one: craft a lot of toxicant or tranq arrows: Step 2: find a BAD BOI REX:step 3: put arrows in bow or crossbow(crossbow recommended for durability:step 3 SHOOT AWAY WHEN IT STARTS RUNNING ON A FAST MOUNT LIKE A RAPTOR:step 4: use your fast mount to catch it: step five: finish knocking it out: step 6: SHOVE RAW PRIME MEAT DOWN ITS THROAT AND BOOM YOU HAVE A REX. Press up if you find this helpful.😃