The house is the home of Dracula, a real vampire who happened to be Mystery Inc.'s nextdoor neighbor.
History[]
Scooby-Doo! Mystery Cases[]
The gang walked into his house after hearing strange noises going on, unknown to them, they encountered Dracula and his monster buddies celebrating his birthday, but he didn't take to kindly of their presents and hissed at them to leave.
During the duos panic, Scooby bumped into a boombox and it started playing music, this brought the attention of one of Dracula's party guests into a dance off with Scooby.
He was beaten, but was impressed by his skills and Dracula decided to allow the gang to become guests.