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. Upon Ymir's defeat, the three brother's crafted the Earth and Heavens from his body, the oceans from his sweat, (some cases from his blood) the trees were crafted from his hair, his eyebrows were used to make Midgard (one of the nine worlds), his bones made the mountains, his skull is what formed the sky, and from his brains they created the clouds.