This is possibly the worst thing I've ever seen. Long before Vincent Price rapped on Michael Jackson's "Thriller," before his stint on Alice Cooper's "Welcome to My Nightmare," he took part in this atrocity, the Bee Gees' Cucumber Castle.
Price plays the evil vampire Count Voxville, and Barry and Maurice Gibb play two princes of a kingdom that's been divided in half so they can each rule a kingdom for themselves. As seen in the above clip, Vincent schemes to get Barry and Maurice to kill each other in a spurious duel so he can inherit the chamberpot for himself. And that's more thought than the people making this atrocity put into it, honestly. You can glimpse comedy great Eleanor Bron in the clip above, and if you stick with this terror, there's also Lulu, Eric Clapton, Mick Jagger, Spike Milligan and other celebs. And the film's catchphrase is "My cucumber and I welcome you." There's a great user review of this 1970 made-for-TV disaster here.
I found out about Vincent Price's darkest hour, incidentally, by reading the special Famous Monsters issue on Price, which is chock full of weird bits of info, including an article on his career in noir films, an interview with Alice Cooper about being led around on a leash by Price, and a lengthy Q&A with Price's daughter. Well worth checking out.