deviruchi hat
A somewhat-famous item in the Korean MMORPG Ragnarok Online, it has a rather high level requirement and confers a small bonus to strength and intelligence. You can identify it as a black or dark-purple hat similar to a beanie with two tall ear-like protrusions and a mischievous facial expression that makes it look a lot like the monster, Deviruchi.
See also
This tag implicates hat (learn more).