Hymir is a sea giant, the husband of Hrod, who lives at edge of the heaven. He possessed an enormous cauldron which the Aesir coveted to brew beer in and Thor was sent to obtain it.
In the final battle against the gods, Hymir will sail the terrible ship Naglfar, which is made entirely from the nails of the dead. The flood that precedes Ragnarok will free the ship after which the giants will board it and, with Hymir as commander, sail towards the battlefield of Vigrond.
Thor asked Hymir if they could go fishing together. Hymir laughed at the young man. "You are too weak and small. You couldn't row the boat properly and you wouldn't be strong enough to survive the freezing winds out in the ocean." (See Midgard Serpent)