|King Mosh and the Savage Raptor Mount|
King Mosh can be found in the north western part of Un'Goro Crater patrolling in a few different locations around The Screaming Reaches. I have indicated the locations where he can be found in red on the map below.
He drops the typical green item and a fairly high amount of experience for people leveling who come across him.
In my opinion, although King Mosh has been nerfed through the ground and there isn't much of a challenge in taming him any more, he still makes a nice hunter pet. He matches really well with the Savage Raptor TCG mount plus it's always nice to know that your pet is rare even if nobody else does. ;) If your having trouble finding him and simply want this skin, there are a few other devilsaurs in game that you could tame, two of which are right in the same zone. The level 54-55 elite Tyrant Devilsaurs can be found patrolling all over Un'Goro, in the south western part of the zone there is also the level 55 elite Devilsaur Queen. If your feeling a little more ambitious, you could also tame King Dread (level 76 elite on normal mode, 82 on heroic) in Drak'Tharon Keep.
King Mosh is an exotic pet. Although he is only level 55, he cannot be tamed by anyone lower than level 69. You must have the top-tier talent from the Beast Mastery spec to be able to tame him.
Like other devilsaurs, he fears. A whole heck of a lot. I can imagine this wouldn't be life-threatening to anyone trying to tame him, but it sure is ultra annoying. As you can see in the video below he feared me a good couple times before I could finish the tame.
He can be found with NPCScan. You will need to add it, his NPCid is 6584.
You can also use this macro to help find and tame him:
/tar King Mosh
/cast Tame Beast
I'm not sure as to what his spawn timer looks like, but if it's like any of the other rares since Cataclysm I'm sure that it is a lot shorter than it used to be.