Koffing is a round, limbless purple Pokémon filled to the brim with toxic gases. Several crater-like protrusions on this Pokémon's body give it the resemblance of a naval mine or a meteorite. Koffing has a skull and crossbones below its blissful face. Koffing has been considered to be related to Grimer, who is also a purple Poison-type Pokémon that associates with pollutants. Koffing may also be related to Drifloon, who is also a floating, round, purple, "X"-bearing Pokémon with a tendency to explode.