Fantominus

Red +2: Almost invisible, this gaseous POKéMON cloaks the target and puts it to sleep without notice.

Yellow: Said to appear in decrepit, deserted buildings. It has no real shape as it appears to be made of a gas.

Gold +2: With its gas-like body, it can sneak into any place it desires. However, it can be blown away by wind.

Silver: Its thin body is made of gas. It can envelop an opponent of any size and cause suffocation.

Crystal: It wraps its op­ ponent in its gas- like body, slowly weakening its prey by poisoning it through the skin.

Ruby / Sapphire: GASTLY is largely composed of gaseous matter. When exposed to a strong wind, the gaseous body quickly dwindles away. Groups of this POKéMON cluster under the eaves of houses to escape the ravages of wind.

Emerald: When exposed to a strong wind, a GASTLY’s gaseous body quickly dwindles away. They cluster under the eaves of houses to escape the ravages of wind.

FireRed: A being that exists as a thin gas. It can topple an Indian elephant by enveloping the prey in two seconds.

Diamond: This Pokémon’s body is 95% made up of gases, which are blown away by strong gusts of wind.

Pearl: A Pokémon born from poison gases. It defeats even the largest foes by enveloping them in gas.

Platinum +6: Born from gases, anyone would faint if engulfed by its gaseous body, which contains poison.

SoulSilver / X: Its body is made of gas. Despite lacking substance, it can envelop an opponent of any size and cause suffocation.

Omega Ruby / Alpha Sapphire: Gastly is largely composed of gaseous matter. When exposed to a strong wind, the gaseous body quickly dwindles away. Groups of this Pokémon cluster under the eaves of houses to escape the ravages of wind.

Sun: Should a strange light be seen flickering in an abandoned building, Gastly is lurking there.

Moon: Although Gastly is barely visible, when it’s near, a faint sweet smell lingers.

Ultra Sun: It’s said that gas emanating from a graveyard was possessed by the grievances of the deceased and thus became a Pokémon.

Ultra Moon: Poisonous gas comprises 95% of its body. It’s said that the remaining 5% is made up of the souls of those who died from the gas.

Let's Go Pikachu / Let's Go Eevee: Said to appear in decrepit, deserted buildings. It has no real shape, as it appears to be made of a gas.

Legends: Arceus: Gaseous and completely impalpable. Also highly dangerous— inhaling part of its poisonous body will cause one to faint instantly.