Similar to a "show down" in the old American West, the deities of ancient Korea would have magical one-on-one battles - but never to the death. Which is cool.
Metamorphosis magic is unique in that it doesn't involve incantations or components, rather it is based on the wits of the caster. The battles began with the weaker of the two morphing into an animal of his/her choice followed by the opponent's morphing into a pursuer/predator of said animal. The battle moves on from there - each deity, in turn, altering his shape to outwit the other. An excellent example of this can be found in Sandman issue #4 "A Hope In Hell". Here Dream and Choronzon square off in a seedy nightclub in Hell, the prize being Sandman's helm of office.
No harm comes to either opponent, it is a test of strength only. The contest ends when one deity gives up - Komodo dragon style.
Examples in Korean Mythology of such contests can be found in the stories of Habaek and T'alhae.
On E2 itself? All we've got is Everything-Proof Shields.