Weezing is a Poison GasPokémon. It is a two-headed, purple Pokémon. They often have gases around them because they are so toxic. The biggest head has a skull and crossbones. The mid-sized head only has a circle. Apparentally, they can also have three heads according to the DPP Pokédex, possibly a deformed conjoined circle between the two.
Weezing loves the gases given off by rotted kitchen garbage. This Pokémon will find a dirty, unkept house and make it its home. At night, when the people in the house are asleep, it will go through the trash.
Weezing alternately shrinks and inflates its twin bodies to mix together toxic gases inside. The more the gases are mixed, the more powerful the toxins become. The Pokémon also becomes more putrid.
By diluting its toxic gases with a special process, the highest grade of perfume can be extracted. To Weezing, gases emanating from garbage are the ultimate feast.