Someone oughta draw the Adventure Time characters as Marvel superheroes-

Finn as Captain America (er, Captain Ooo perhaps)
Jake as…Mystique? (shapeshifting)
Marceline as Scarlet Witch
Simon Petrikov/Ice King as Bruce Banner/Hulk
Princess Bubblegum as Black Widow
Lady Rainicorn as Thor (she’d carry the hammer in her mouth, obviously)
BMO as Iron Man
Flame Princess as the Human Torch
Huntress Wizard as Hawkeye

And so on.