If you’re having trouble finding the Argie on Ark Survival Evolved (Mobile), I find it is most common near the top of mountains in the redwood forests (Middle of the island). An easy way to escape if you’ve aggravated the Argie is try to fly away on a pteradon. Good luck!
If you ever encounter one in the wild, and you are in an early stage in the game, run the opposite direction. Also try not to agrovate it unless you are up to the KO/Fight.
Good luck if you encounter it!