The Crystal King is a character that appears in Paper Mario. He appears in Chapter 7 as the boss of the Crystal Palace, holding the last Star Spirit hostage.
Strategy
The Crystal King has 60 HP, and 1 DEF. He has a variety of abilities, including spawning small crystal bits by his side, spawn duplicates of himself, and healing himself for 20 HP. In addition, he can shoot an ice beam at Mario, which if not guarded properly against, will freeze him for a few turns.