Pumpkin

As far as playable characters are concerned, Pumpkin is a strange one. Unlocked after clearing out the game as Joachim Armster, Pumpkin has little reason to actually exist in the game. Created as a joke by series-head IGA, the character was thrown in simply as a lark, something funny to laugh at while you went through the game one more time. He has no story, nothing really special about him. He's just a weird little kid-like doll with a pumpkin for a head that kills vampires.

Although funny for the creators (and certainly amusing as a one-off lark for players), Pumpkin as a charater would have made more sense if he were anyone else, or if pumpkin children has shown up ealier in the series. There are other enemies they could have used instead that might have sold the joke to unknowing audiences more (which was eventually the case with the inclusion of the Old Axe Armor as a playable character in Portrait of Ruin). As it is, he's a joke without much of a punchline, really.

Give the creators credit, though, as they did know how to try and sell a joke. After Lament of Innocence, ol' Pumpkin was included in the follow up, Castlevania: Curse of Darkness as one of that game's "innocent devils", the powerups that the game's hero, Hector, uses to explore the castle. So at least the creators had fun with this weird little dude.