Master Ball

The Master Ball is the best and rarest ball available in any game. It was originally manufactured by Silph Co. in Saffron City, but only a few were produced before Team Rocket tried to steal them. Since then they have been discontinued. From then on, the few remaining prototypes were only given to accomplished Pokémon researchers. Because of this, only one can be found normally in each game (although it can be won in each generation after the first; it is the grand prize for the Lucky Number show, Lilycove City's Lottery, and at the Jubilife TV station, respectively). It has a two-shade purple top forming two brighter purple circles on the sides of the top, as well as the letter "M" printed on the top. The Master Ball has a 100% chance to catch any Pokémon, no matter what the circumstances and could be described best as "the ball that never fails". You can only get one in every game as an object, and the only way to get more without cheating is winning the Lottery, or trading from another game. It is possible to get 450 master balls without cheating.

Trivia

 * It can catch any Pokmon.
 * It is considered the most powerful Pokeball.