Answer: Sidney

Although we all know the lovable blue cookie-consuming puppet as Cookie Monster, the monster with a sweet tooth once had a proper name before his passion for cookies became so consuming it turned into his very identity.

Somewhere long ago in a puppet nursery, there was a tiny little blue puppet named Sidney, destined to delight children everywhere with his comical and messy cookie eating antics. In 2004, during the song The First Time Me Eat Cookie, Cookie Monster reveals “Me was just a mild-mannered kid. In fact, back then, me think me name was Sid.” and then later, via the official Sesame Street Twitter feed in 2010, Cookie Monster recounts “Me wasn’t born with name “Cookie Monster”. It just nickname dat stuck. Me don’t remember me real name… maybe it was Sidney?”

Poor, Sidney. All it took was a cookie eating bender (possibly with the Keebler Elves) and the sweet, sweet, sugar rush to turn him into a name-forgetting cookie addict.