The Red Murderer is an American animated film based on the horror film series using various cartoon characters.
A scientist and his assistant are developing a brand new toxin. As the toxin was completed, it turns out to be a complete failure. They dump it into the saliva boats where the saliva workers have been burned off by the toxin who has subsequently morphed into an anthropomorphical alien-like creature with claws that can generate pyrokinesis.
Mordecai and Rigby are in Duel Masters Academy in there exchange program. Rigby puts a bucket in Chancellor Sheppard's door and as he opens the door, the chum splatters all over himself. They receive a Saturday detention and Sheppard blames Mordecai for what Rigby is doing. At Saturday detention, there comes Yakko, Wakko and Dot playing there scripts (Yakko speaks too much, Wakko acts Australian and Dot becomes insane). Sheppard returns and blames Mordecai again. They are setenced to a tree by Sheppard and the Warners so Sheppard can keep his appointment with his pedicure. Then the lights shut off for an unknown reason.
A rave party, similar to Freddy vs Jason, is happening with kids waving glowsticks, sucking on pacifiers, sporting 1980s clothing and using dance movements from the 1990s while drinking alcoholic beverages, in the woods. As Heidi Wienerman, a raver, goes to the bathroom to wash up, the fire guy (dubbed as Furno) attacks Heidi. Two party animals are seen drinking vodka coming up and they see Furno dressed as a chicken, thinking he's there friend Fernandez make jokes but end up getting badly burned. An alarm system was ringed and Jimmy Kudo: High School Detective, answers the call and is on the case to find the curious murderer.
In the cave of the Sahara, the Warners are being chased by an angry Arab named Riff Raff Samash who keeps on abusing his camel. When he loses them, he goes away. The Warner finds the home of two big game hunters Devereaux and Hoskins, from England who are trying to find the diamonds. They steal the diamons they had and they both suspect each other causing them to shoot guns out at eachother.
The Bravest Warriors are speaking weird gibberish approximating the Welsh tongue and as they are doing missons, they come across two caveman toasting marshmallows (voices of Jess Harnell and Daniel Davis). They witness the characters' muteness and actions and they believe thwey are Neanderthals, which the two caveman are actually intellegent Cro-Magnons named Monte and Shine. They are seen toasting more marshmallows and enjoying there chicken but then the fire grows bigger and transforms into Furno. Furno greets the caveman and kills them. He then infiltrates the scanners and knocks out Chris Kirman and Beth Tezuka.
This act continues with Act 5. At an Italian restaurant, Vito (one of Mike's multiple personalities in Total Drama) is seen with a villanous gang when Furno comes in and asks for volunteers for his new crime spree. Not amused, Vito orders his men to get him but he burns Vito and some punks which they happeningly agree. Jimmy Kudo finds out news about the recent crimes and burnings and he sees a survivng girl named Stella Load. Stella explains to him of how he saw a man in red. Meanwhile, Furno is seen gloating to the fact that his plan is working. They meet up with Sanji who is gambling on cockfights and they force Sanji to talk with puppies. Sanji squeals and says that Furno is having a meeting at the Purple Pit (based on the same location from the Nutty Professor), a nightclub located on the other side of town before escaping.
A couple of teens are being hopspitalized, including a grown chef man (voice of Mike Judge) who has a bleeding fork stuck in his brain during a barbecue causing him to shout out barbecue lines and cooking references (Pickles?l Wheres the pickles? You want cheese on that medium rare?). A girl with a broken leg takes his number and she does into her hospital room and sees a bunch of people stuck in the nuthouse.