Triboniophorus Tyrannus

“

Burn in hell, you mumbling abomination! Click to listen — The Spy to the Pyro

”

The Triboniophorus Tyrannus, known to the community as the "Brain Slug," is a community-created headwear item for the Pyro and was chosen by Valve to be released with the first wave of community-contributed content due to its outstanding quality. It appears as a green, gelatinous slug attached diagonally atop the gas mask of the Pyro's head.

Trivia

• This hat is a reference to the brain slugs that occasionally appeared in the animated television show Futurama, where they would be attached to someone's head, controlling their mind, forcing them to appear semi-comatose and talk in a monotonous tone.
• The Triboniophorus Tyrannus is one of the few hats that are jiggleboned, meaning that they will jiggle around realistically with the player's movement.
• The Triboniophorus is a type of green slug native to Australia. "Tyrannus" is Latin for "tyrant" or "king."