Let's lead off with Squaresoft's action-RPG classic Secret Of
Mana, probably the best co-op RPG for three players ever made.
Midway through the game, you travel to the Ice Country where you
meet... a reindeer. Hmmm. He tells you that his master has been
kidnapped by a monster and taken to the Ice Palace. Well, since
this is an RPG, y'all better rescue him. After hacking and
slashing your way through the palace, you face the Frost Gigas.
Beat the crap out of this icy giant and you'll discover that he
actually is Santa Claus! Once you've knocked the evil out of
him, he'll give you a Boomerang Orb and send you on your way.