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Methanosians, also known as Homo Palustris[1][2][merch 1] are a humanoid plant species from the planet Methanos.

Their evolved counterparts are Evolved Methanosians.


Methanosians are a humanoid plant-like alien species with a green and black colored body with root-like feet, seemingly holding rocks. Also, their shoulders and head have red and yellow petals. Methanosians can either have four or five fingers.

Methanosians are taller than an average human and have a distinct rotten stench that worsens with heat.

So far, only male Methanosians have been seen, so it is unknown what female Methanosians look like.

Before they hit puberty, they have black faces and their petals and facial structure are different. But at the age of 16 Earth years, they slowly blossom in their mature form.[3]


Methanosians evolved from carnivorous swamp plants.

At some point, Methanosians evolved into herbivores.

Powers and Abilities

Methanosians have the ability to ignite methane in their palms similar to a flamethrower. After their blossoming, they ignite methane from holes in their palms. Their fire blasts are precise enough for them to shoot a cage with Kevin and Gwen in it, while the cage melted and Kevin and Gwen were left unharmed,[4] as demonstrated by Swampfire.

Methanosians are capable of limited flight through means of launching fire from their palms as jet propulsion, much like Pyronites.[5] They are also capable of breathing fire, as demonstrated by Swamps.[6]

Methanosians have a high degree of chlorokinesis,[DJW 1] being able to telepathically interface with plant life, manipulate and instantly create biological agriculture, and generate a gas that makes exposed plant life elongate, enlarge and ensnare enemies, seemingly being mutated by the gases. Some plants have a brief green aura when they influence them.[7]

Methanosians can generate seeds from their bodies that phase into or pierce into any ground or flooring before turning to vine tentacles strong enough to restrain a Highbreed[8] and a Chimera Sui Generis.[9] They usually are as small as pebbles, but they can sometimes become larger and sharper if used on a metal surface.[9]

A Methanosian's body can generate a type of mud that sticks to everything but them, which Swampfire used to blind Negative Humungousaur, as the latter could not pull it off his eyes and had to change into Negative Big Chill to get rid of it.[10]

Methanosians are capable of regenerating and regrowing any damaged or destroyed body parts, allowing them to grow back lost limbs, holes in their body, or even their head. Swampfire was even able to reform his body from remains when it got splattered to pieces.[11]

Methanosians are also able to heal other people's wounds as demonstrated when Reinrassig III lost his hand when he saved Ben from a Rodilia Dentia.[2]

Another method of regeneration involves reattaching detached body parts. This is accomplished by manipulating their vine-like "veins" and tentacles to reach out and meld with the insides of the detached limb and return them to the body, allowing them to reconstitute automatically if damaged.[12]

A Methanosian's methane has a very pungent smell that is intolerable to some species like the Incurseans, which will make them retch and faint.[4] Using their methane abilities, Methanosians can produce "sleeping spores" that can render humans unconscious.[13]

Methanosians have enhanced strength, as Swampfire was able to push over a Highbreed Weather Array using leverage by turning his feet into roots running deep into the ground.[14] Similarly, he was able to pull himself out and resist the gravitational force of a Null Void portal,[15] and even hold his own against Vilgax with his bare fists.[9] In his "blossomed" form, he appears to be even stronger than before.[3]

A Methanosian's body structure allows them to walk straight through thin spaces such as the gaps between iron bars.[4] When Swampfire was crushed under a large container, his body deformed into vines that burrowed through and then out of the ground to reform him instantly. In the same instance, Kevin punched Swampfire in the torso, resulting in his fist getting stuck in it until Swampfire punched him back. Additionally, Swampfire was shown to be immune to laser bolts, as they simply passed right through him and seemed to tickle him.[12]

Methanosians are able to extend their fingers and feet into long roots that can dig through rock.[7]

Methanosians are capable of jumping exceptionally high.[14]

Methanosians have rather strong teeth that are able to injure another Methanosian.[3]

Methanosians can generate vine-like tentacles from their backs.[16]

Methanosians can grow plants from the ground simply by raising their hand, though they only gain this ability after "blossoming".[3]

Also after "blossoming", Methanosians gain the ability to grow vines with a flame tip from their hands and use them as whips, which are able to slice the plasma generated by Ball Weevil's species,[17] as demonstrated by Swampfire.


Despite their regeneration, Methanosians can be continuously cut up by sharp objects, such as a Polymorph's Anti-Gravity Projector, preventing them from regenerating.[11]

Methanosians can be harmed by electricity, such as that generated by a Conductoid.[17]

Methanosians can be immobilized by ice, such as the ice breath of a Necrofriggian, though they can thaw themselves out by igniting the methane in the palms of their hands.[18]

A Methanosian's fire attacks can be canceled out by fire extinguishers.[19]

Methanosians are vulnerable to magic, as Swampfire's back was scorched by a magic attack from Charmcaster (while empowered by the Alpha Rune armor).[3]

Swampfire's body heat can make it difficult for him to fight opponents that are attracted to heat, like reptiles.[20]

Methanosians can be immobilized and overpowered by the gravity powers of a Galilean.[17]

Like other organic beings, Methanosians are vulnerable to being aged to dust by the time rays of a Chronosapien or a Chronian.[21]

Despite their enhanced durability, Methanosians can feel pain from being bitten by another Methanosian.[3]

A Methanosian's plants can be killed using liquid chemicals, such as a spray used by the Stalker.[19]

Methanosians cannot control sentient plants, let alone weeds.[22] This is no longer a weakness once they "blossom".[3]

Despite their enhanced strength, Methanosians are physically weaker than Crystalsapiens,[DM 1] Tetramands, and Vaxasaurians.[DM 2]

Video Games

In the Ben 10: Alien Force (Video Game) timeline, Methanosians can channel their flames into a concentrated fireball or fire beam, tunnel underground and burst in a coating of flames.

In the Ben 10 Alien Force: Vilgax Attacks timeline, Methanosians are capable igniting their hands for "flaming fists", creating a ring of fire, and causing thorny vines to sprout from the ground.

In the Cosmic Destruction timeline, Methanosians are able to ignite plants they are controlling.

Notable Methanosians

Notable Methanosian Hybrids


The name Methanosian is a play on "methane".

Their alternate name, Homo Palustris, is derived from the Latin words "homo", meaning "man", and "palustris", meaning "swampy" or "marshy".


  • Methanosian blooming reflects the blooming practices of real-life flowers.
  • SevenSeven is scared of Methanosians.[DM 3]



  1. Ben 10: Alien Force Volume 4 DVD; file

Crew Statements

Derrick J. Wyatt

Dwayne McDuffie

Sapient Species
AcrosianAerophibianAmperiAnoditeAppoplexianArachnichimpArburian PelarotaAtrocianBiot-savartianCelestialsapienCerebrocrustaceanChimera Sui GenerisChronianChronosapienChurlCitrakayahConductoidContumeliaCrystalsapienDetroviteDracosianDragonsEctonuriteFloraunaGalileanGalvanGalvanic MechamorphGeochelone AerioGimlinopithecusGourmandHighbreedHulexHuman (Osmosian)IckthyperambuloidIncurseanKineceleranKraahoLenopanLepidopterranLewodanLimaxLoboanMaxatomarMerlinisapienMethanosianNaljianNecrofriggianNemuinaNosedeenianOpticoidOrishanOrthopterranOryctiniPantophagePetrosapienPiscciss PremannPiscciss VolannPlanchakülePolar ManzardillPolymorphProtostPrypiatosian-BPugnavorePyroniteRevonnahganderSegmentasapienSlimebioteSonorosianSotoraggianSphoeroidSplixsonSylonnoidSynthroidTalpaedanTetramandThep KhufanTo'kustarTransylianUxoriteVaxasaurianVladatVreedleVulpimancerZaroffian
Unnamed Sapient Species
Argit'sAstrodactyl'sAtomix'sBall Weevil'sDagger AliensDecka'sEnforcer Alien'sGutrot'sHobble'sKickin Hawk'sMedic'sMole-Stache'sPakmar'sPickaxe AliensProbity'sStone CreaturesTack'sTechadon Weapon Master'sTiny'sToepick's
Evolved Sapient Species
Evolved AppoplexianEvolved ArachnichimpEvolved Arburian PelarotaEvolved GalileanEvolved GalvanEvolved HumanEvolved MethanosianEvolved NecrofriggianEvolved Polar ManzardillEvolved SonorosianEvolved To'kustarEvolved VaxasaurianEvolved Vulpimancer
Non-Sapient Species
Airborne Clown VirusAldebaran BeidafangsAnubian BaskurrBuglizardCassiopeian Dream EaterChupacabraCorrupturaCrabdozerDasypodidaeDravekGracklflintHavok BeastHumpbackusKaosseffexx UltimasauriaLucubraMuroidNanochipNull GuardiansOmnivoraciousPallorfangPanuncianPsycholeopterranQuartilloptusRodilia DentiaRoot SharkSand RipperScreegitScrutinSlammoidTerroranchulaVicetopusVolaticus biopsisWigzelian Org BeastXenocyteZiboson
Unnamed Non-Sapient Species Evolved Non-Sapient Species
Cyber SquidsLiving MushroomsMucilator'sSquid MonstersTime Beasts Evolved Panuncian
Non-Canon Sapient Species
Sool & Gontu's Species
Non-Canon Non-Sapient Species
Cyber Squids (Vilgax Attacks)