Weezing uses Poison Gas as its attack, which is similar to Koffing's attack in Super Smash Brothers. A cloud of gas will come out of the holes in Weezing. Any character that makes contact with the Poison Gas will take damage. If a character is stuck in the center of Weezing's attack, then they will also take damage continuously. Weezing is the most damaging pokemon in Melee, being able to deal well over 100% if someone is to stay in the center of a Weezing. But an intelligent player will simply DI out of Weezing's attack, minimizing damage. It is interesting to note that Weezing can deal extreme damage to Giga Bowser as his very large size keeps him from escaping Weezing once trapped within. It is possible for Giga Bowser to accumulate over 300% from Weezing, making Weezing very valuable in The Showdown and in the Giga Bowser battle in Adventure Mode. Weezing's attack does not harm the summoner.
A giant balloon of Weezing (in actuality, the 3D model of Weezing used in Pokémon Stadium for Nintendo 64) is one of the many floating and bending "platforms" that comprise the Poké Floats stage. The balloon starts out big and actually decreases in size over time.
Weezing features as a collectible trophy, unlocked as one of the 100+ trophies that can be collected randomly during normal play, such as in the Trophy Lottery and throughout the various Single-player Regular Matches. It reads as follows:
The evolved form of Koffing, Weezing is basically a pair of Koffing fused together. They tend to float in the air and emit gas or noxious smoke from the outgrowths that cover their bodies. As strange as it may seem, diluting Weezing emissions as much as possible creates one of the most exquisite perfumes known to man. (Pokemon Red & Blue 9/98)