Stalking Piranha Plants are new enemies in New Super Mario Bros. Wii. They appear as common enemies in World 5 (NSMB Wii) and in World 6 (NSMB Wii) as rare enemies. When Mario isn't around they are walking on two legs. However, when Mario approaches they stretch their necks, which blocks Mario's path. Stalking Piranha Plants also go back walking on two legs, if they have stretched their necks for too long. That means you can be around and Stalking Piranha Plants may be walking on two legs. Four Stalking Piranha Plants appear in World 5's Enemy Course. Stalking Piranha Plants can be defeated by a fireball from a Fire Flower (NSMB Wii), hit by a Starman, or being hit by a shell. Stalking Piranha Plants can be defeated via being frozen by an iceball from an Ice Flower, however, you are unable to pick up the frozen block they're in. To get rid of them, you must Ground Pound the ice block they're in.