In Super Smash Bros. Melee
As a Poké Ball Pokémon
Celebi is very special among the Pokémon who can be summoned. First of all, it must be unlocked; it won't appear out of a Poké Ball until all playable characters and stages have been unlocked, the Sound Test has been unlocked, all Event Matches have been completed, and Score Display has been unlocked. Once the requirements have been met, the chance of Celebi appearing is 1/251 ("251" being the total number of Pokémon in existence at the time of Melee's release), just like the other "unlockable" Pokémon, Mew. (Both have a double-chance of appearing in Event 37: Legendary Pokémon, though a 2/251 chance still isn't that huge.)
Like Mew, Celebi's action is not an attack; Celebi gently flies off the screen a few seconds after it's summoned, without saying its cry. The summoner is subsequently awarded the rare Celebi Catcher bonus worth 8,000 Points; the first time this is achieved it yields a special achievement message and earns the Celebi trophy.
As a trophy
Celebi, as with all other Pokéball Pokémon, features as a collectible trophy; this trophy must be specifically earned by encountering Celebi once during any match. This makes it one of the hardest trophies to earn, because essentially, the entire game must be played through before the 1/251 chance of Celebi appearing in a Poké Ball is put into effect, and that is a very rare occurrence indeed; throwing 251 separate Poké Balls does not guarantee one appearance by Celebi among them. This can be made easier by setting the game to only spawn Poke Balls and have the ratio "Very High." Its description reads as follows:
- Celebi has the power to travel through time, and thus wanders from one age to the next. It is considered a deity by the forests: plants and trees are said to grow in abundance wherever Celebi visits. Like Mew, Celebi is shrouded in mystery. Its special techniques blend grass and psychic powers.
- Pokémon Gold & Silver 10/00
In Super Smash Bros. Brawl
Celebi appears in Super Smash Bros. Brawl, along with other returning Pokémon such as Entei, Suicune, Lugia, Ho-oh, Mew, Chikorita, Moltres, Staryu, Togepi, Electrode, Bellossom and Wobbuffet. It drops trophies when summoned. After first seeing Celebi, a notice saying that it has been seen for the first time and "It is a rare event indeed" will appear. Celebi will drop either stickers, trophies or CDs onto the stage.
Mew, Jirachi, and Celebi appear 1/493 of the time individually. This has given some evidence to the secret Pokémon Arceus, the only one out of 493 not revealed at the time of Brawl's release.
A Time Travel Pokemon. Celebi can travel throughout time and inhabit multiple places simultaneously. It is said that it appears only during times of peace, greeted by a flourishing of grass and trees. Two turns after Celebi uses its Future Sight move, the foe is bombarded with psychic energy. This proves to have a devastating impact on any Pokemon. (Pokemon Gold/Silver)
In Super Smash Bros. for 3DS and Wii U
This Pokémon has the unique ability to travel through time to the past or future. However, the only times Celebi wants to visit are those of peace, so catching sight of Celebi in one of the beautiful forests it frequents is a good sign indeed. Perhaps it's mankind's responsibility to create the kind of time Celebi would want to visit.