It’s not mentioned in the preview whether or not he’s a good liar, so it’s possible his “trick” is to loudly claim that he loves being hit by weapons and hates having healing spells cast on him. That sort of thing.
Manglemire is for five players at level 65, so keep that in mind before you make any cyclops-stomping plans for July. The dungeon is only one piece of the overall update, so fans should keep their eyes peeled for more previews as the update draws closer.
Source: Official Site