Monster Mash

Films-Animated

 * The citizens of Halloween in The Nightmare Before Christmas include living skeletons, ghosts, zombies, witches, vampires, a werewolf, a Big Red Devil, a Monster Clown and a Mad Scientist with his stitched-together creation, along with many original monsters.
 * Scooby-Doo on Zombie Island has ghosts, zombies and Witches were-cats.

Music

 * The Trope Namer is "Monster Mash", a classic 1962 novelty hit by Bobby "Boris" Pickett and the Crypt-Kickers. Sung by a Mad Scientist with a Boris Karloff-type voice, it mentions his monster, vampires, (including Dracula and his son), the Wolf Man, Igor, zombies and ghouls. Pickett recorded several additional tunes in the same vein, most notably the Christmas-themed "Monster's Holiday".

Theme Parks

 * The Haunted Mansion has ghosts, zombies, and a mummy throwing a raucous party in a seemingly abandoned (and very haunted) mansion. The Haunted Mansion Holiday adds the citizens of Halloweenton to the mix.