Later in Impel Down, Buggy revealed a modified version of the Buggy Ball, renamed the Special Muggy Ball (特製マギー玉,Tokusei Magī Dama?), which he compacted into a size small enough to be concealed inside a person's body. Its appearance is a bullet-sized red sphere.
Despite its small size the Muggy Ball retains the full destructive powers of the Buggy Ball (in essence, similar to a hand grenade). This was first used against the Minotaurus, where Buggy kicked the Muggy Ball from the tip of his shoe, and the resulting explosion injured the Jailer Beast severely, but it was still conscious and standing. In the anime, the ball leaves his shoe after a small hole opened up on the bottom of the sole. Buggy also attempted to use a Muggy Ball against Dracule Mihawk, but he managed to deflect the Muggy Ball back towards Buggy using his sword.
Buggy throws a Muggy Ball from inside his shoe.
The Muggy Ball flies right in front of Minotaurus...
...and then releases a devastatingly powerful explosion.