Fear the Gear! Trophy in Skylanders Imaginators
Fear the Gear!
Equip an Imaginator with all Ultimate Gear
How to unlock Fear the Gear!
This will most likely come naturally while you play, as most bosses will award you with Ultimate gear every now and then. Kaos will often give you three different Ultimate gems each time you beat him.
If you missed this before you are done with the campaign, you can farm these by replaying a level, or doing M.A.P battle events. (Note: The inventory menu is located in the pause menu while having a creation crystal placed on the portal.)