Mega TNT Barrel
From the Super Mario Wiki
When used, a TNT Barrel automatically appears above each racer besides the player who uses it. They all drop at the same time, making the racers lose all Wild Moves and temporarily have their controls reversed and being unable to use items. Although Kremlings get an extra effect from most items that appear out of blue balloons, the effect is not altered no matter who uses it, Kremling or Kong.