King Croacus IV, or King Croacus the Fourth, is a flower boss in Super Paper Mario found in the Floro Caverns. He is the king of the Floro Sapiens and brainwashes Cragnons. He is the son of King Croacus III. He rather doesn't care much about fighting, but decides to dispose Mario, Peach, and Bowser when they enter his castle and they battle.
When Mario and co. first battle, they must jump on Croacus IV's smaller heads, due to the center head and the biggest one being invincible unless the smaller heads are exposed at him. He also throws sharp petals at players as another attack which Mario and co. must dodge. He can also be defeated with Thoreau getting one of its heads and throwing it back at his face. After a long battle, Croacus IV collapses and it becomes revealed that the Floro Sapiens mind controlled Cragnons to save Croacus IV's people.