Grouping these costumes by category seemed pretty easy, but there was a few that I just couldn't classify, so enjoy this odd menagerie of randomness. Nothing can top the random bizarreness of the Rubik's Cube costume, and the Visible Man outfit at the bottom of the page is just plain creepy.
Baboonman, Baron Balthazar from The Curiosity Shop, Circus Queen, Circus Trainer, and Doctor Doolittle (with crazy half mask)
Fortune Teller, Heidi, Indiana Jones, Mr. Tickle, and Mr. Twiddles
Rubik's Cube, Secret Agent Man, Spy Girl, and 2 incredibly odd Slinky-Themed costumes with actual Slinkies built in to them. Sadly, the Slinky sponsored John Holmes outfit never made it to the stores.
Tarzan, The Cat, Uncle Sam, Wanda Kay (a very obscure Hardy Boys supporting cast member), and Willow
Beatnik, Candy Striper, Go-Go Girl (dancing cage not included), and 2 dirty hippies
Rock and Roll Girl, and The Visible Man