The megalania is a very fun creature to use but it is not worth taking it unless you want to have a bit of fun. They are pretty weak to and personally I don’t think they should take Extraordinary kibble. I have a 225 one with 334.3 Melee and it only does 34 damage. They are also sooo slow so you spend half of your levels in speed. Also they are in a very dangerous place because you can normally only find them in a cave which is not safe at all. On ragnarok they spawn in the volcano biome were the wycern trench is and they also spawn around all bugs like mantis, areno, arthroplura, titanaboa and of course the dung beetle. The volcanic biome also have rexes and all other trouble. A lot of alpha spawn there and it is right next to the highland biome were gigas spawn and they tend to wander in the volcanos biome, so megalania are really not that good at all
The best tame for caving as you can skip otherwise hard areas and dangerous enemies by just crawling on the wall or ceiling plus it can fit in tight spaces and you can use weapons while on back, making it a must for caves
These things are amazing at the golem cave, just walk on the wall and avoid all enemies but the bats, make sure you upgrade some weight into them, and just use a good pile to kill the bats instead of taking forever biting them
You can breed them while they are mounted on the wall. I found it's the best way to breed them because they don't move around. But be carefully their egg goes to the other side of the wall so make sure you have access to both sides.
I love these guys. Don't think of them as standard battle mounts. I use mine to have a really fun time tracking and hunting down creatures in the Ragnarok canyon. Because you can shoot from it's saddle, you can wait to ambush potentially dangerous creatures from the walls and bridges. By far my favorite hunting mount.
Once tamed they are actually okay at swimming and excellent guard animals for if you're base gets raided just put them on the ceiling and when someone breaks in it drops on them and gives them rabies which will generally kill them quickly
These things can stay hooked to any surface even when unmounted. If you live in a cave or wanna set an ambush leave them hooked to the cave entrance ceiling on agressive and taunt your enemies to follow you into the cave.
They'll shit their pants trust me...