In Norse mythology, Ymir (also Aurgelmir, Brimir, or Bláinn) is the ancestor of all jötnar. He is described in the Poetic Edda and in the Prose Edda. Ymir was killed by Odin, Vé and Vili. From Ymir's body they made seven worlds. Bïfrost and dwarves evolved from maggots by burrowing into Ymir's dead body.From that, dwarves can punch dents and burrow into rock.