Ben 10 Fan Fiction Wiki
Ben 10 Fan Fiction Wiki
This page was the Featured Alien of March 2017
General Information
Species: Impostherba
Home World: Terranoia
DNA Source: Unknown Impostherba
Body: Humanoid Plant
Powers and Abilities
Abilities: Imitation
Plant Growth
Classification: Flora
First Appearance: TBA

Capgrass is the Omnitrix's DNA sample of an Impostherba from the planet Terranoia. He is free for anyone to use.


Capgrass's abilities include:

  • Imitation
    • Capgrass can take on the form of any organism he touches, imitating their physical appearance and properties flawlessly.
  • Plant Growth
    • Capgrass can cause various plants to spontaneously burst from any surfaces he touches.
  • Plant Merging
    • Capgrass can merge with his body with various forms of plant life.
  • Regeneration
    • Capgrass can regenerate from any injury that doesn't entirely destroy his body.


Capgrass is a plant-like humanoid alien with an extremely lean body. He has long, thin arms, two legs comprised of twisted tendrils, and a cap-like organ on the top of his head. A patch of long grass grows from his back, and seaweed-like tendrils grow from the bottom of the cap and dangle in front of his face.


Capgrass is incredibly weak to fire, and is vulnerable to weed killer and the like.


If Capgrass appears in your series, make sure to note his appearance(s) here.

Planet and Species Information

Capgrass is an Impostherba from the planet Terranoia. Terranoia is a waterlogged planet covered in toxic swamps teeming with various plants and wildlife. The planet is under a constant state of quarantine, with no unauthorized civilians allowed onto or off of the planet's surface. Authorized personnel that go down to the planet's surface for whatever reasons are required to carry flamethrowers and stay in groups of at least three men at all times. If the teams must split up for whatever reason, a direct line of sight is to be maintained with the other members of the team in question. Though the toxic swamps present a mild danger to those not wearing biohazard suits, the true danger of the planet comes from the Impostherba themselves.

The Impostherba are the dominant predators on Terranoia. They blend in perfectly with their swampy environments, both literally and figuratively, and are practically impossible to find. They will only attack lone prey, often tracking groups of prey for long periods of time and waiting for a member of the pack to be left on its own. Common wisdom says that if an Impostherba shows itself to you, you might as well already be dead.

An Impostherba first incapacitates its prey by entangling it in rapidly-generated vines. Once the victim is longer capable of moving, the Impostherba will force one of its slender arms down the prey's throat. Two of its elongated fingers will go into the victim's trachea, and two will worm their way into the cavities of the victim's head. The Impostherba will proceed to generate a grass-like plant inside of the victim's body, eventually causing them to asphyxiate. During this process, blades of the grass may be seen growing out of the victim's eye sockets. Once their prey is dead, the Impostherba will drag the corpse down into the swamp, leaving behind no evidence of the attack.

Aside from their formidable hunting tactics, the primary thing that makes Impostherba so dangerous is their ability to impersonate other lifeforms. After killing their prey, an Impostherba will often take on their appearance and seamlessly blend into the group the prey was a part of. From there, the Impostherba will wait to be alone with other members of the group and begin picking them off one by one. This tactic is so dangerous that a lone Impostherba brought onto a space station for study was able to wipe out the entirety of the crew within several days. As such, any personnel that strays away from their team for more than a period of thirty seconds during expeditions to Terranoia will be assumed to be an Impostherba, and will promptly be neutralized on the spot.

Despite their relatively animalistic methods, the Impostherba are sapient, and are capable of speech. However, most will refuse to speak to or even acknowledge the presence of another person in the area until the two are alone, in which case the Impostherba will promptly attack. Security footage exists of the aforementioned research station incident, although the Impostherba cannot be seen on-camera until attacking its final victim. When questioned why it had killed the researchers, the Impostherba paused for a moment, then simply said, "It was something to do.". The security footage cuts out after that, with later investigation showing a grass-like plant having grown inside the camera's circuitry. No further research on the Impostherba has been approved at this time.



  • Capgrass was based off of the Capgras Delusion, a disorder where those affected believe that a close family member or pet has been replaced by a nearly identical imposter.

The CaT Collection

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