From the Super Mario Wiki
A Mini Zinger

The Mini-Zinger is an item collected from a Blue Item Balloon that appears in the game Donkey Kong Barrel Blast.

If the player gets a Mini Zinger and uses it, a swarm of Zingers attacks those behind them as an obstacle. If any players run into the swarm, they are attacked and their speed drops. The victim must accelerate to get rid of them. If Mini Zingers are used by a Kremling, the effect lasts longer.