Mad, Mad, Mad Monsters is a 1972 traditional animated 43min+ film produced by Rankin/Bass Productions in the United States and animated overseas by Mushi Production in Japan. It originally aired on September 23, 1972 as part of The ABC Saturday Superstar Movie and is a "prequel of sorts" to the 1967 stop motion animated film Mad Monster Party?
The animated comedy was released to DVD on July 12, 2011, along with another Rankin/Bass animated special called Jack O'Lantern (which I posted here), but is now out of print. Official DVD's are going for $50 to $100+ on ebay, but there is a bootleg DVD-R selling for $20 at etsy.com. Or you can watch below, here is the synopsis:
SYNOPSIS: After Baron Henry von Frankenstein creates a Bride for his Monster, he invites all of Universal's greatest classic monsters, including Count Dracula, his son Boobula, Ron Chanley the Werewolf, the Mummy, the Creature, Dr. Jekyll and Mr. Hyde, Claude the Invisible Man and his equally-invisible family, and a giant gorilla named Modzoola, to gather at the Transylvania Astoria Hotel for the monster and his bride's midnight wedding on Friday the 13th.
You can watch the full special at xumo.tv click here or watch below from YouTube.