Guardian Angel (Adventure Time)

The Guardian Angel is a character in "Dungeon." She seems to help Finn by healing him of his wounds and taking him to the Chamber of the Crystal Eye. However, the Guardian Angel soon transforms into a hideous monster and puts Finn into a cage, intending to eat him in a stew. She can remove scars, mend clothes, and heal wounds by touching that person with a lit finger. She also carries snacks. Her appearance is deceptive, as the Guardian Angel is a monstrous angel not of protection, but death,

Her guise is that of a blue-skinned female angel with long white hair, white bird-like wings, and a poofy white dress. Her monster form on the other hand is mostly the same, but with an evil old woman/zombie-like face.