AQ20 is a really nice transmog farm. The worms called Silicate Feeder are actually the mobs with the best loot in the raids so be sure to loot them. They are found between the 3rd and 4th boss. Be sure not to kill ANY of the mobs in the room with the 2nd boss as that will start the encounter for the boss. You can go through the whole instance without killing any bosses, so you can choose to run the entire raid or exit after killing the worms by creating a group in the group finder and leaving it.