Pyro is a large Lava Bubble; Cryo is a large Frost Bubble.
Pyro and Cryo will both hop out of their pools [Pyro in lava, and Cryo in water] like normal Bubbles, and shoot elemental balls, Pyro shooting fireballs, Cryo shooting iceballs. At the begining of the battle, Mario is automaticaly given a Yoshi, he must use the Yoshi to swallow a fire or ice ball, and spit it at the opposite element Bubble, (ie: iceballs at Pyro, and fireballs at Cryo). Getting hit causes the damaged Bubble to shrink, Mario must hit Pyro or Cryo 3 times to defeat them, if either Pyro or Cryo is taken out; the remaining Bubble will flee, ending the battle. You can use power-ups to attack.