Master Ball

The Master Ball (マスターボール, Masutā Bōru), is a item in Super Smash Flash 2. The Master Ball, unlike its incarnation in Super Smash Bros. for Nintendo 3DS and Wii U, it captures any character it comes in contact with instead of releasing a legendary Pokémon. Anyone trapped in the ball can break out of it. It works similarly to 's Egg Lay or being encased on ice, in which the character who trapped their opponent inside of the ball, can deal damage to them. The ball can also be re grabbed and thrown, after someone has been captured. It is unlocked by clearing event match #36: Gotta Cherish Them All.

Origin
The Master Ball is a variety of Poké Ball introduced in Generation I, and arguably the rarest of all Poké Ball variants. Developed by Silph Co., it is unique in the aspect that it is guaranteed to catch any wild Pokémon that it is thrown at. Normally, only one can be legitimately obtained per save file, without recurring to other game elements such as hacking or winning one by luck on the Pokémon lottery.

Trivia

 * The concept of an opponent-catching Poké Ball was first pitched in the early stages of SSF2 ' s development in the form of a Premier Ball, another Poké Ball variant. Whether Master Ball's concept was inspired from this idea or if it is merely coincidence is yet to be disproved.
 * The Master Ball is currently the only unlockable item in Super Smash Flash 2.
 * In the same event match required to unlock the item, an item modeled after the Cherish Ball is used instead of the Master Ball. This item is functionally identical to the Master Ball, except it ignores stage collisions and passes through platforms, allowing easier KO's.