River Piranha Plants are enemies in New Super Mario Bros. Wii. They are a type of Piranha Plant that appear in World 5 (NSMB Wii). They live in rivers. River Piranha Plants don't seem to have bodies. They attack by spitting a spiked green ball up and bring it back down. Touching the spiked ball, or the River Piranha Plant itself will damage Mario. River Piranha Plants can be defeated by throwing a fireball from a Fire Flower (NSMB Wii), or an iceball from an Ice Flower. Then ground pound on the Ice Block to defeat the River Piranha Plants. Since the River Piranha Plants are in water, you are unable to pick up the frozen ice block.