Adventure Time/Recap/S06/E24 Evergreen

Millions of years before the start of the series, a mutated dinosaur by the name of Gunter (voiced by Pamela Adlon) and the ice elemental Urgence Evergreen (voiced by Kenny) try to save the planet from a comet by constructing a magical crown that will grants its wearer their one true wish. Although the two are able to secure a power supply for the crown, Evergreen is incapacitated before he can use it, resulting in Gunter placing it on his head; however, Gunter accidentally wishes to be an ice wizard like Evergreen, marring the crown for all future wearers, including the Ice King.

(Recap copied from Wikipedia, "Adventure Time (season 6)")


 * Wham! Episode: To be expected of the episode that is the origin of The Crown.