Prior to 2293, they were largely believed to be mythical by citizens of the Federation. In that year, Captain James T. Kirk and Doctor Leonard McCoy of the Starfleet starship USS Enterprise-A encountered a Chameloid named Martia in the Klingon prison colony on Rura Penthe. McCoy later theorized that the Chameloids were native to that asteroid, given Martia's apparent adaptation to cold weather. Martia herself said she was from Arc. (TOS movie: Star Trek VI: The Undiscovered Country, CoE eBook: Ghost)
Following the Dominion attack on the Antwerp Conference in 2372, a Chameloid named Wusekl was illegally detained and imprisoned on Triex, as the people believed he was a Founder. (ST novel: Articles of the Federation)
In the late 24th century, Federation archaeologists on Drura Sextus discovered Tholian crystal-lattice documentation of a race of genetically engineered shapeshifters. Two of these shapeshifters were responsible for the deaths of Dr. Jennifer Almieri and Counselor Han Duren on Earth in 2377. Captain Montgomery Scott theorized that these shapeshifters were Chameloids, given the proximity of Drura Sextus to Klingon space. (CoE eBook: Ghost)
- Bart Faulwell states in Ghost that Martia was the only Chameloid ever on record; however, at the time of this story, Wusekl's case was still sealed by court order on Triex.
In an alternate timeline in which Counselor Deanna Troi of the USS Enterprise-D died in 2368, a Chameloid, Lieutenant Blair, was the science officer aboard the USS Enterprise-F in 2408. (TNG novel: Imzadi)