Crippler is a level 65 bone golem that spawns in the southern part of Terokkar Forest. He can spawn in a few different locations including the Ring of Observance (which is in the center of Auchindoun) and Northwest, Northeast and Southeast of Auchindoun in the bone wastes. (His patrol routes are highlighted in blue on the map above.)
He seems to share the typical spawn timer as other rares in Outland, but I have read on some Wowhead comments that it may be possible to move up that timer a bit by killing broken skeletons outside of Auchindoun. How true that is I don't know, more than likely it could have been a coincidence that Crippler spawned right after killing a few skeletons for them. I've never experienced this myself.
Crippler drops one noteworthy item, and that is the Dragonbone Ring. It is a level 63 boe ring with a random enchant.