I was watching a vid of a Guild downing C'thun, and before they fought him they were all mounted on very large beetle like things. I was just wondering If any one could tell me what they are called, where you get them and any differences from a normal mount. Thanks on advance!

The item they come from is resonating crystals, they can only be used in AQ, but I believe otherwise are identical to other mounts.

There are one or two legendary bug mounts on each server from the AQ opening event (needed to turn in sceptre of the shifting sands for it), it can be used outside AQ and is instant cast rather than 3 sec.