The Grim Adventures of Billy and Mandy - Season 7 - Eps 16: Dracula Must Die!
When vampire hunter Lionel Van Helsing prepares to kill Dracula, Billy, Mandy, and Grim arrive to stop him since Dracula is just senile and harmless. Van Helsing reveals the source of his hatred: in the past, he and Dracula were "best friends forever", until Dracula used his irresistible dance moves to marry Tanya, the woman of his dreams. Tanya arrives too, revealing that she is none other than Irwin's grandmother, making Irwin one-quarter-vampire on his father's side and half-mummy on his mother's side. Van Helsing leaves, but Dracula is unsatisfied with his newfound family of nerds.
About The Grim Adventures of Billy and Mandy

Title: The Grim Adventures of Billy and Mandy
First Air Date: 2001-08-24
Last Air Date: 2007-11-09
Status: Ended
Rating: 8.045/10 (from 958 votes)
Language: EN
Seasons: 8
Total Episodes: 184
Network: Cartoon Network
Genres: Animation, Comedy, Kids
Production Companies: Cartoon Network Studios
Synopsis
The exploits of the Grim Reaper, who has been forced into being the best friend of two children. A spin-off of the show Grim & Evil.
Cast

Greg Eagles
Grim (voice)

Richard Steven Horvitz
Billy (voice)

Grey DeLisle
Mandy (voice)

Vanessa Marshall
Irwin (voice)