"Vapor" is one of the many placeholder names given to a set of backgrounds for an unused final boss of Mother 3. It is believed to be a form of Claus, the brother of the game's main protagonist Lucas and one of the top commanders of the Pigmask Army as the Masked Man, but very little is known about it and as such, much speculation has arisen over what its original intended role in the game was to be.
Forms[]
"Dung Beetle"[]
This form is given the placeholder name "Dung Beetle" (the same as a type of enemy that appears in the game). It resembles a deformed robotic version of Claus, with an entirely silver body, white eyes, a red "x" on its forehead and what appear to be metal tubes running down its arms.It attacks using PK β, which poisons all party members. It sometimes drops a Silver Dragonfly when defeated.
"Tent Person"[]
"Tent Person" is the placeholder name given to a form that resembles an angelic version of "Dung Beetle". It is mostly golden yellow and has wings. It can attack using PK γ, which causes paralysis to all party members.
"Snow Bunny"[]
The placeholder name "Snow Bunny" refers to a form which appears to be Claus naked. It uses only PK Ω (Hypnosis Ω) to attack.
"Clayman"[]
"Clayman" resembles regular Claus with his clothes on. It's placeholder name appears to be taken from the Clayman type of enemy that appears in the game. It possesses a non-PSI ability with the text "The Barrier Pose made the dissipate!", which causes all party members to cry.
"Vapor"[]
"Vapor" refers to an ominous grey background resembling a cloud shaped like an "x", with a slimmer red "x" occasionally lighting up inside of it. It is unknown if the red "x" seen in it is connected to the red "x" on "Dung Beetle"'s forehead. It uses an ability with no text whatsoever that creates feelings of strangeness in everyone. It could be Brainshock Ω.
"Straw"[]
"Straw" refers to a dark red outline of Claus that resembles the later form "Rope Snake". It gives 6666 experience points when defeated, but if defeated with any level of PK Love, it grants the player an extra 330 experience points for a total of 6996 experience.
"Aeolia's Table"[]
"Aeolia's Table" resembles Claus's head, but with white eyes and an open mouth that appears to be screaming. It has a similar ability to "Straw" and "Rope Snake", albeit one that causes fleas. Its attack is the same as Vapor's, but it causes nausea instead of strangeness. It only uses physical attacks if you use Brainshock on it twice to make it feel strange.
"Sign"[]
"Sign" has an appearance similar to "Clayman", albeit it moves wavily in place rather than floating upward.
"Train"[]
"Train" appears as Lucas's sprite transposed onto Claus's.
"Sign" (2)[]
"Sign" shares its name with the earlier "Sign" form but looks very different, appearing as a metallic Claus with red eyes.
"Vapor 2"[]
"Vapor 2" appears a large red head with its mouth open, giving the appearance of it screaming. When defeated it drops the Factory Sketch, a map of the Factory, as a normal item rather than a key item.
"Rope Snake"[]
"Rope Snake" appears to be Claus's head with white eyes and his mouth open, similar to "Aeolia's Table", but much more detailed.
Theories[]
Because of how little is known about the unused final boss, many theories have sprung up surrounding it. Some suggest its meant to be a representation of how Lucas sees Claus throughout the fight, while others believe it may be a result of Claus losing control of his powers. Others believe it may be the result of Giygas, the final boss of Earthbound, possessing Claus but this seems unlikely as the game's creator Shigesaki Ito has said he always intended Mother 3 to be "brother vs. brother".