Monster In My Pocket (NES, 1992)
Monster In My Pocket started as a line of toys released by Matchbox and ultimately expanded to comic books, video games and more. The toys were first marketed in 1989 with the NES game being released by Konami in 1992 and was loosely based on the comics.
The game is a one or two player platformer and there are two characters to choose from, the Vampire and the Monster. Despite the generic cast, the game is actually a pretty decent platformer. Oddly, the Asian release was turned into a different game by replacing the playable characters with Batman and The Flash. It was titled, appropriately enough, Batman & Flash though it was otherwise basically the same game.