Big & Small Tire
From the Super Mario Wiki
Big & Small Tire is an offensive item in Mario Kart Arcade GP and Mario Kart Arcade GP 2. When shot while the aiming is correct, it travels to opponents and hits them, thus briefly slowing them down for a moment. After the hit, opponents experience their tires shrinking and growing continuously, which makes them lose control and speed. After a while, the item effect goes away.