In Mario Kart World, which item temporarily makes a driver giant-sized?

In Mario Kart World, the Mega Mushroom temporarily makes a driver giant-sized.

The Mega Mushroom enlarges the racer, increases their power and allows them to flatten opponents by driving over them. Its effect changes the balance of a race for a short time, letting a driver force through crowded sections and recover positions.

The ordinary Mushroom is a common source of confusion because it gives a speed boost, but it does not enlarge the driver. The Super Star grants invincibility, and the Bullet Bill turns the racer into an automated high-speed projectile. Those items offer different advantages even though all can dramatically change a race.

The Mega Mushroom originally appeared in Mario Kart Wii before returning in Mario Kart World. Its inclusion connects World to earlier Mario Kart mechanics while fitting the newer game's 24-driver races and broad interconnected routes.