Dogars

Dogars 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 has been seen in the anime. 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. Dogars's purple skin is very thin, and over-inflation can cause it to explode.

Dogars 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 Dogars to hover. When agitated, it creates a more toxic gas and expels it through the holes in its body.

(Source: Bulbapedia)