Thor was known as the "Thunder god".  His day of the week is Thursday.  His worst enemy was one of Loki's monstrous children - the World Serpent.
       The World Serpent was an enormous snake which wrapped around the world and bit his own tail.  Thor has met the Serpent two times.
       The first encounter between Thor and the Serpent was at a giant's hall.  The giant laughed at Thor for being weak.  The giant challenged Thor to pick up an old cat sitting by the fire.  Thor, who was the strongest of the gods, tried to lift the cat, but it didn't even budge.  Thor tried so hard that he ended up picking the cat up a few inches off the floor.  The giant was astonished and told Thor to drop the cat.  Thor had really picked up the World Serpent in disguised.
       The second time Thor and the World Serpent meet was when he went fishing with another giant.  Thor used an ox's head as bait and the World Serpent took it.  Thor nearly hauled it aboard and the giant became frightened and cut the line, so the World Serpent escaped again.
       The third time they will meet will be at Ragnarok, the end of the world.  Thor will see the serpent and attack it and kill it, but will be poisoned by it's venom.