Ultimate Similamander is the Ultimatrix's evolved form of Similamander. He is an evolved Mimewt from the planet Alpha Proxima. He is a free-to-use Ultimate alien, along with his non-evolved counterpart.


Ultimate Similamander resembles his non-evolved counterpart, but now red in coloration, and significantly taller, almost double the size of his previous counterpart, with a broader chest.

Ultimate Similamander has developed a trio of sharp, curved horns emerging from his scalp, large triangular spikes emerging from his back and running down his tail, claws emerging from each of the heels of his legs, and a small, but sharp barb emerging from the tip of his tail. Along with this, Ultimate Similamander's eyes have become slightly slanted, granting him an angrier look.

The Ultimatrix symbol remains on the center of his chest.

Powers and Abilities

Ultimate Similamander's ability to replicate the specific abilities and powers of any opponent he faces has become immensely enhanced, allowing him to maintain up to 75% of the power from abilities he mimics and retain it for up to 6 hours, as opposed to an hour at most. Even when the replicated power becomes to fade at the end of the 6 hours, it degrades slowly.

Ultimate Similamander can maintain several replicated abilities at once, up to around 10 different sources of DNA. More would be possible, but begin to put an immense strain on Ultimate Similamander's body, the strain's comparison ranging to mild vertigo to a painful, constant migraine.

Ultimate Similamander can also absorb the internal DNA energy from one's energy by making physical contact with them, allowing him to more rapidly absorb and mimic their abilities. Essentially, he can mimic the abilities of an individual faster by making physical contact opposed to only making eye contact.

Ultimate Similamander can replicate the anatomy of his opponents upon absorbing their internal DNA energy, allowing him to shapeshift better and more extensive than his non-evolved counterpart. For example, non-evolved Similamander could gain the bipedal, muscular structure of a Tetramand, while Ultimate Similamander can also gain a Tetramand's additional appendages, such as their extra eyes and arms.

Ultimate Similamander can allow now replicate the abilities of inorganic species, such as Galvanic Mechamorphs and Chronosapiens by transforming and shapeshifting his cells at a molecular level to grant him "pseudo-inorganic" anatomy. For example, he can transform his body into the liquid metal physiology of a Galvanic Mechamorph but deep down, the "liquid metal" is still considered organic.


Ultimate Similamander's enhanced ability replication still suffers from limitations, such as being able to only absorb 75% of the strength of abilities he replicates, keep them for up to 6 hours without the presence of the DNA source before they eventually begin to slowly degrade, and maintain several replicated abilities at once, up to 10 different sources of DNA he has absorbed from. Stated above, absorbing more is possible, but would begin to put an immense strain on Ultimate Similamander's body that would gradually worsen the more he attempts to absorb.

Ultimate Similamander has a highly-aggressive, almost-primal nature that will override the personality of Ultimatrix users who transform them, unless they have a form of highly-enhanced intelligence, such as a Galvan. Ultimate Similamander's primal nature is similar to the aggressive personality Omnitrix users take on when using an Appoplexian form. Even while being wielded by a user of high intelligence, Ultimate Similamander also expresses an envious, greedy nature that his primal nature normally blankets over. If Ultimate Similamander is in a situation where he has has the chance to gain more power, even if it may negatively impact him, he may still go for the power.

Ultimate Similamander is able to absorb the abilities of artificially-evolved aliens, such as other Ultimate forms, but only a small amount, as a large amount would cause Ultimate Similamander's sanity to be disrupted and turned completely primal, transforming Ultimate Similamander into a hyper-evolved beast of animalistic nature, constantly growing bigger, stronger, and more aggressive the more artificially-evolved abilities he gains, causing mutations to his body, such as enlarged horns, back spikes, and claws and the anatomy of Ultimate aliens he gains becoming more and more melded into his physiology overtime.

Ultimate Similamander still retains a major drawback that his non-evolved form also suffers from: the fact he additionally absorbs the weaknesses of DNA sources.




Ultimate Similamander is a free-to-use Ultimate alien, so feel free to use him in your own series.



  • The original Similamander was created and designed by user Aaronbill3, and is also free-to-use. User Alanomaly also came up with Similamander's nickname.
  • Ultimate Similamander shares many similarities with Ultimate Wildmutt, such as his red coloration, addition of back spikes, and enhanced strength.
    • In fact, Ultimate Similamander's theoretical voice actor would be Dee Bradley Baker, doing a high-pitched impression of Ultimate Wildmutt.
  • The idea that Ultimate Similamander can gain abilities from a maximum of 10 different DNA sources at a time was inspired by the symbolism of the number 10 in the Ben 10 franchise.
  • If Ultimate Kevin's mutation in Ben 10: Ultimate Alien was part-Evolved Mimewt, he most likely would have absorbed the abilities of the Celestialsapien baby, due to Ultimate Similamander's greedy nature.
  • Ultimate Similamander can in fact gain the abilities of a Celestialsapien, but due to the limitations of his ability replication, he can gain 75% of their maximum power. A Celestialsapien-empowered Ultimate Similamander can warp sections of reality and even create a planet or two from a simple thought, but is nowhere near omnipotence.
    • If Ultimate Similamander were to absorb DNA energy from an evolved Celestialsapien, he'd explode. (citation needed)
  • Despite Ultimate Similamander's more aggressive personality, he's still a baby.
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