Triple Finish (さんみいったい（共通） Trinity (Common)) is the Pokémon Trainer's Final Smash. It is the same regardless of the Pokémon that grabs the Smash Ball. The trainer brings out all three of his Pokémon. Charizard then uses Fire Blast (which is also the final move used to send the opponents flying), a large star-shaped flame (its shape could also be compared to the Japanese character for "fire"), Squirtle uses Hydro Pump, a multi-directional spray of water, and Ivysaur uses SolarBeam, a narrow beam of concentrated light, to create a massive projectile which can hold targets in place within the blast. It does more damage to players that are closer to the Pokémon, where all three moves will hit at once. When an opponent is as close as possible, they take about 57% damage. However, a downside to this Final Smash can be if the opponent is too close, they will be sent straight up by a concentrated ball of energy in front of the Pokémon, and then can avoid the attack. The move can be used in mid-air, in which case the team will hover. After several seconds, the Trainer recalls the other two Pokémon and the Final Smash ends.
While using it, a box of text (like the ones in Pokémon games, based on the ones from the fourth generation games) appears on the bottom of the scene, which states, "Take that! Triple Finish!" (which the Pokémon Trainer also screams out loud), and later "It's super effective!". It should be noted that the second message only pops up if the attack causes damage to opponents; if it misses, the first message will remain for the duration of the attack. The text box blocks damage meters and appears in Snapshots. The camera also zooms in on the trio, slowly zooming out as the attack goes on.
Description from the Instruction Booklet
Charizard, Squirtle and Ivysaur team up to release a trio of powerful attacks consisting of Fire Blast, Hydro Pump and Solarbeam.
The Final Smash of the Pokémon Trainer. Squirtle, Ivysaur, and Charizard join forces to simultaneously use Hydro Pump, SolarBeam, and Fire Blast. This is the only time all three of them appear on the screen together, so this move boasts the strength of three in one. A window will appear on the screen, but don't worry about it.
All three of the attacks have featured in every main installment in the Pokémon franchise. In the early generations, these moves were known as being the strongest moves for their types (Water, Grass, and Fire respectively). They each have a very high base power of 120 in Generations I-V but have a drawback to offset this: Hydro Pump has an accuracy of 80%, Fire Blast has an accuracy of 85%, and Solarbeam must be charged before it can be used (depending on weather conditions).
The phrase "It's super effective!", displayed in Brawl if the attack hits, has always been used ever since the first generation in the series - during battles, whenever the type of attack used by the Pokémon is used on a foe that is weak against said type of attack, it would deal double the normal amount of damage. A Fire-type attack used on a Grass-type Pokémon would be an example. The game would display the message "It's super effective!", and the sound used to indicate damage changes as well.