Hilary Briss was a character in the BBC Comedy The League of Gentlemen and was played by Mark Gatiss. He also appears in the movie The League of Gentlemen's Apocalypse as one of the three protagonists, appearing more as an anti-hero in contrast to a villain like on the show.
The League of Gentlemen (TV Series)
Hilary appears as somewhat a mysterious man and the owner of Hilary Briss & Sons, the local butchers shop in the town of Royston Vasey. His wares include a secret foodstuff known as the "Special Stuff", which, while never revealed, is said to be as immoral as it is illegal. A small group of high authority figures are in on Briss's activities, all of whom are helplessley addicted. Among this group includes Police Inspector Cox, Magistrate Maurice Evans, and Counciler Samuel Chignell.
During the second season, the Special Stuff led to an epidemic in Royston Vasey, resulting in the deaths of many from chronic nosbleeds. Maurice's wife Eunice got her hands on the Special Stuff after Murice got her and the rest of his family addicted, and began putting them in her sandwiches which led to the massive epidemic. While a pure dose of Special Stuff distributed by Briss is relatively safer to consume, Eunice cut hers up and mixed it in her paste, making it poisonous; however, repeated consumption of Hilary's Special Stuff will eventually result in nosebleeds. Hliary himself does not take the Special Stuff, as he himself says that "someone has to stay in control".
While Cox, Sam, and Maurice were arrested by the authorities, Hilary fled to a tropical island before he could be caught, leaving behind his wife (who was revealed to be a massive brown cow). Bris continues to sell the Special Stuff, this time in the form of burgers, which become very popular on the island.
Hilary doesn't appear in the third season, but a newspaper headline reveals a string of nosebleeds occurring in the Caribbean, most likely all down to Briss. His shop is also seen boarded up, with numerous graffiti that includes "Murderer" sprawled over it.
The League of Gentlemen's Apocalypse
Hilary returns for the feature length movie as an anti-hero and one of the three protagonists alongside Herr Lipp and Geoff Tipps. Hilary is seen on the run from the police in handcuffs being chased across the moors. He takes Herr Lipp hostage and stops Geoff's car. They arrive at a church and end up in a room which opens a gateway to the real world. They are confused at first, but are told by Papa Lazarou and Tubbs and Edward that they were fictional creations and sends Briss along with Lipp and Geoff to seek out The League of Gentlemen who had abandoned Royston Vasey to work on other projects.
Briss has Steve Pemberton kidnapped and lures Mark Gatiss and Reece Sheersmith to Royston Vasey to show them the destruction of the town. Characters from the League's new project "The King's Evil" including villain Dr. Pea arrives and tries to convince Briss to join him in the King's Evil world, but Briss refuses to abandon Royston Vasey. Briss fights a massive monster created by Dr. Pea, and is victorious until Pea stabs him in the back. Briss dies in Geoff's arms and convinces him to save Royston Vasey before dying. Geoff later avenges Briss by killing Dr. Pea.
The special stuff
It is never revealed in the show what exactly the "special stuff " is. It is a highly addictive yet immoral substance which causes heavy nosebleeds to those who consume it. It is likely that the "special stuff" is cocaine, as misuse can cause addiction and nosebleeds due to the damage to the nasal passage. When cocaine is cut, it can be even more dangerous. Other clues to the ingredients is the fact that Briss's surname is a pay on the Yiddish word bris, a slang term for the Brit Maleah, the Jewish circumcision ceremony. This suggests that there are foreskins in the special stuff.