Wear your armour take your best longneck (I use asc 240 and it works with decent riot set) and shocking darts also take very good pump shot-gun and fly around redwoods in flyier...
When they pounce you spyglass it and if it's bad lvl kill it with shot-gun if it's lvl they you want shoot him with shocking darts and fingers crossed that you can do it (if u have like at least 800def, like 200-250HP and 180 longneck (have to use shocking) it will most likely work) u can also take some med brews just to be sure he won't kill you.
1. Make a bear trap and crossbow with tranq arrows or a longneck with tranq darts
2. Go into the Redwoods on any map, DO NOT fly on anything because the Thylacoleo can jump out of trees and take out your flyer, on Scorched Earth it spawns pretty close to the Wyvern Trench, so be careful
3. Look for a decent Thyla, I’d recommend 145-150 you can usually find them chasing a Gallimimus
4. Place down a bear trap and lure the Thyla into the trap
5. Repeatedly shoot it in the head with whatever you’re using to knock it out
6. Once it’s knocked out, place COOKED meat in its inventory, it’s the only creature that prefers cooked meat over raw. You can also use Extraordinary kibble, which is produced by Magmasaur, Yutyrannus, Deinonychus, Rock Drake, Wyverns and Hespornis(golden egg)
7. Name your new Thylacoleo! It provides a bleeding effect to any wild creature, it can also climb vertical surfaces and pounce on creatures, it’s one of the best cave clearers out there!