In the episode Graybles 1000+, there was these 'ice thing' that was chasing Cuble. That ice thing was actually not Simon, if you all could have guessed it. Because in the episode Evergreen, Gunther wish that he want to be like Urgence Evergreen when he wears the crown. So whoever wears the crown will share the same characteristics and appearance as Evergreen. There is possibility that Betty will find a cure for Simon, if she ever recovers from being a mad wizard in You Forgot Your Floaties, or someone smart enough to cure him, like Princess Bubblegum.