Could this be a remnant of the Original Gunter inside? Would this also explain why Penguin Gunter hung around Ice King for so long despite him being a total whack job? On top of this, there are clues during Penguin Gunter's flashbacks in 'Orgalorg' that would suggest his name was Gunter long before he met Ice King. In 'Orgalorg', Penguin Gunter managed to snap himself out of the trance to stop the suffering he was causing. In 'Hoots' Dream Gunter toppled Princess Bubblegum, but afterwards couldn't explain why he did it, saying that 'It just felt like the right thing to do'. If Original Gunter were to have been successful in his wish to become like Evergreen, but was then perhaps consumed by the essence of the comet, becoming Orgalorg, could this be a subconscious clue to that? It also often seems at times that Gunter does not wish to be evil. This may be a coincidence, but you can see that when Orgalorg transforms into Penguin Gunter, he does not have those feet (I don't know Gunter's gender so I'm going to use he for ease). If you look at Evergreen and Dream Gunter's feet, they kind of look the same. I've not got a lot to go on, but a few things made me draw the connection. Gunter (a.k.a Orgalorg, i.e Penguin Gunter) is Gunter (i.e mutated dinosaur brain Gunter, Original Gunter)

Gunter adventure time