This film is in the vein of Hillbillies in a Haunted House. High in camp, and it doesn't take itself too seriously. The plot involves decide to spend the night in a haunted house, but it's the headquarters of a mad scientist, a werewolf, and a gorilla. It was originally a "spookshow" where actors in costume would rampage through the theater!

https://en.wikipedia.org/wiki/Monsters_Crash_the_Pajama_Party