Patch 3.2.0 (04-Aug-2009): The ravasaur trainer Mor'vek has returned to Un'Goro and will offer to help Horde players raise and train a Venomhide Ravasaur as a mount... if they can survive the creature's deadly poison.
This troll was removed sometime prior to patch 2.3.0.
The troll is currently in game, and can be found in the marshlands near the entrance to Un'Goro Crater. (South side)