Trap Flex

Trap Flex is the Quirk used by Habit Headgear.

Description
Trap Flex allows Habit Headgear to flex his trapezius muscle to extreme degrees, allowing him to cover his whole head with his shoulders. The flexing gives him a fair amount of speed and strength.

Weaknesses
While Trap Flex does provide extreme speed and strength, it is nowhere near as strong as other strength-based Quirks, such as One For All, as All Might was able to knock Habit out with a single blow to the back of the head.

Trivia

 * Trap Flex is also referred to as Oversized Trapezius in My Hero Academia: The Strongest Hero's combat archive.