Koffing is a spherical Pokémon filled with toxic gases. It has vacant eyes and a wide mouth that usually has two pointed teeth in the upper jaw. However, a full set of teeth is shown in the Pokémon the Series: Black & White episode Rocking the Virbank Gym! Part 1 (EP083). Below its face is a cream-colored skull-and-crossbones marking. Several geyser-like protrusions, which usually release a mustard-colored gas, cover this Pokémon's body. Koffing's purple skin is very thin, and over-inflation can cause it to explode. The Pocket Monsters Carddass Trading Cards depicts Koffing as having a hollow body.

Koffing creates gases within its body by mixing toxins with garbage, and produces more gas in higher temperatures. These gases are malodorous and cause sniffles, coughs, and teary eyes to those around them. The gases are also lighter than air, allowing Koffing to hover. When agitated, it creates a more toxic gas and expels it through the holes in its body. As shown in the Pokémon the Series episode Pokémon Emergency! (EP002), Koffing's gas can be ignited by fire or electricity. It feeds on the fumes of raw, rotting trash found in gas dumps and polluted air. Koffing at one point was plentiful in Galar due to factories. Koffing is most often found in urban areas.

Evolution
Koffing evolves into .
In Galar, it evolves into Galarian Weezing.

(Source: Bulbapedia)