Burn in hell, you mumbling abomination!
— The Spy on the Pyro's favorite holiday destinations.
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.
- This hat is probably 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 brain slug in Futurama appears to have two antennas on their heads and a single eye while the TF2 counterpart has two small black eyes and no antennas.
- However, most likely to avoid copyright issues, this hat looks slightly different then the brain slugs, as the brain slugs have 1 big eye and antennas on its head.
- 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".
- During the 1950s and 60s, the time period in which Team Fortress 2 takes place, sci-fi movies were a fad. The hat is likely also a reference to this.
- This hat is one of the most popular hats to be named because people call it a persons name. for example "Larry"
- This hat is also widely painted because it looks fashionable in all colours.
- This hat when non-vintage is still worth more than a Vintage Respectless Rubber Glove
- When gift wrapped, it shows the item as "Pyro brain slug".
- When killed, the hat remains attached to the Pyro's head, though sometimes (if the "brain slug" is painted) the paint can dissapear and the "brain slug" will turn to it's normal green color again.