Mandy: That's not Santa, you stooge. That's the Grim Reaper.
Billy: Do I still get presents?
The Grim Reaper (Greg Eagles) has come for a soul — specifically, a hamster in his dying days — but he's thwarted from taking the hamster to the afterlife by two children: blissfully idiotic Billy (Richard Horvitz) - the hamster's owner - and his cynical, amoral best friend Mandy (Grey Griffin). The pair challenge "Grim" to a limbo contest to save the hamster; when Grim loses (through Mandy's cheating) he becomes Billy and Mandy's newest friend — and by "friend," we mean that he's contractually bound to cater to their every whim.
Grim is now (begrudgingly) forced to serve as something of an underworld version of Mary Poppins, thanklessly placating Billy's demands for cheap entertainment and Mandy's schemes for self-profit with his magical scythe while desperately trying to find a way to be rid of the duo for good.
Adventures abound as the human duo and their unwilling friend interact with others in their lovely little town of Endsville, facing down all sorts of opponents, from the school bully to sometimes homicidal neighbors to Eldritch Abominations born from the most terrifying pits of the human mind.
Thus goes The Grim Adventures of Billy and Mandy, an absurd Horror Comedy series created for Cartoon Network that combines dark comedy, slapstick, and eldritch horror themes reminiscent of those found in H. P. Lovecraft's novels.
Created by former Cow and Chicken artist Maxwell Atoms, the show was the winner of the first Big Pick, a contest where viewers got to vote what pilot would be greenlit to be the next Cartoon Cartoon. The series was also originally paired up with another Maxwell Atoms cartoon, Evil Con Carne, to make up the Three Shorts show known as Grim & Evil. This early version of the show put more emphasis on the "horror" part of horror-comedy, becoming more goofy and comedic (but still pretty dark) when the two shows were separated into their own series.
The cartoon lasted seven seasons (2001-2008) with two Made For TV Movies; Billy & Mandy’s Big Boogey Adventure and Wrath of the Spider Queen, a couple of specials — including a crossover with Codename: Kids Next Door note — and a spin-off attempt titled Underfist: Halloween Bash.
The 2007 online game The Fright Before Christmas has its own page.
The Grim Adventures of Billy and Mandy provides examples of:
Tropes with their own pages