|Specifics: "Transmetals" logo|
Transmetal (first wave)
In beast mode, the Transmetals seemed almost, if not entirely, mechanical, much like the animal forms of their predecessors. However, as part of a partial "inversion", many of their robot modes bore organic elements, such as Cheetor's furry chest. Transmetals also typically featured a third "mobility" mode. While not full vehicular modes, these half-modes gave aspects of a vehicle to the existing beast forms. Examples included Rattrap as a wheeled rat, Primal as a sky-surfing gorilla, and Megatron as a VTOL-enhanced Rollerblader.
Beast Wars cartoon
The Transmetals were created as a result of Transformers being bathed in a quantum surge after the destruction of the Vok Planet Buster. All the Beast Warriors who were not "born" from a protoform on Earth or shielded in a CR Chamber were altered. Why Earth-"born" Transformers were unaffected by the surge's effects are a mystery, especially considering that protoforms still in stasis pods were affected to various degrees.
The Transmetallized individuals were Megatron, Tarantulas, Rattrap, and Cheetor. Scorponok and Terrorsaur were in the middle of their mutation when they fell into lava pits seeping into the Predacon base and perished. Rampage was Transmetallized in his stasis pod. It's unclear whether he was a true protoform at the time, but when Optimus Primal's spark was transplanted into a fresh new protoform, the resulting form was Transmetal as well. Other protoforms in evidence include Transmutate, who was judged "partially Transmetal", and the Fuzors Silverbolt and Quickstrike, who displayed the Transmetal quality of immunity to the Metal Hunter's weapon. Even a fair bit of time after the surge, Depth Charge was turned into a full Transmetal as he was pulled into a temporal anamoly in space before arriving on Earth in his ship.
Most Transmetals had additional weapons and seemingly enhanced power levels. They were immune to some Vok weapons and did not show up on Vok scanners - Tarantulas took the view that the quantum surge's effects meant they were "one with [the Vok] now".
They are possibly immune to the effects of energon radiation. The evidence of the latter is scant, since most of the energon deposits on Earth's surface had been destroyed or converted to stable energon cubes by the Planet Buster cannon. However, Transmetal Tarantulas was once seen standing beneath an energon cache, completely unaffected. However, this may be due to the fact that the energon was stable as non-Transmetal Blackarachnia was able to hold a cube with no ill effects until she cracked it. More conclusively, the non-Transmetal Inferno suffered energon overload while in a cave containing raw energon crystals while Optimus and Cheetor were unaffected. Cheetor would be somewhat affected , sparking and "energon farting" though not to the extreme extent as before. So partial immunity to the radiation may be an effect of Transmetallization.
In addition to the characters mentioned above, Transmetal toys were also produced for Rhinox, Airazor, Waspinator, Terrorsaur, and technically Inferno. (The Scavenger toy was initially intended to be his Transmetal form, and was so in Japan and the UK.) None of these appeared on the show.
Scorponok, Blackarachnia, and Dinobot, though also not Transmetal in the show, were given their own Transmetal toys as Happy Meal pack-ins from McDonald's. Claw Jaw and Spittor were redecoed and sold as Transmetals in European markets with a VHS tape.
Initial Transmetal toys were not designed with guns, only melee weapons, contrary to the requirements of the animated series (kinda the opposite of the situation with Bludgeon and co.'s toys vs. their comic book depictions). As a result, Mainframe Entertainment was forced to come up with creative solutions to give these characters ranged weapons without diminishing the newly increased toy accuracy of the show. Thus, Tarantulas's handheld buzzsaw functioned like a gun and the green markings on his shoulders were depicted as missile ports, Megatron's pincer/whip/flail/"whiplash cutlass" thing (read: he's holding his damn tail) gained the ability to stiffen and fire like a cannon, and Cheetor's hands, the halves of his Cheetah mode head, were capable of firing energy blasts. In Other Visits (Part 2), however, he fires only one hand.
Even more elaborate was the functional reconceptualization of Optimus Primal's toy, whose hoverboard thruster/mace launcher was used as a laser pistol. Not content with this rather puny-looking firearm, some clever cove at Mainframe noticed that his shoulder-pad and mace-stowing bracket thing could be flipped over his head (a function of his transformation) and improperly positioned in such a way that the long handles of his dual maces pointed outwards like gun barrels and, with the shoulder-pads positioned over his outstretched fists like trigger-guards, the whole device was re-imagined as something resembling two machine guns mounted on a steadicam harness.
The only exception to these exotic re-imaginings was Rattrap, who used his tail/whip/spear as intended but also retained his pre-Transmetal gun (albeit with a redeco to suit his new color scheme), despite the fact that the toy did not (no doubt explained by subspace).
As an odd point of comparison, the later Transmetal Optimal Optimus was packaged with a rifle, which he never used in the show.
Near the end of the series, a new breed known as the Transmetal 2 appeared. These new forms blurred the line between the mechanical and the organic even further, with equal parts of both appearing in both modes in an asymmetrical patchwork-like jumble. This often resulted in somewhat monstrous-looking designs.
Beast Wars cartoon
The difference between a "Transmetal" and a "Transmetal 2" was somewhat vague. Only Cheetor, Dinobot II, and Blackarachnia were explicitly described as Transmetals 2. Each of them was altered by an enigmatic piece of Vok technology known as the "Transmetal Driver", which appeared in Megatron's possession without explanation. Despite lacking the vehicle modes of the previous Transmetals, Transmetal-2-ness was generally viewed as an enviable upgrade. Cheetor, Blackarachnia and Dinobot II all displayed some degree of "supernatural" powers, the use of which was signified by glowing effects in their sparks and/or eyes: Cheetor showed vague visionary tendencies (which, admittedly, had happened before), enhanced healing abilities, and telekinesis ; Blackarachnia demonstrated telekinesis ; and Dinobot II showed enhanced healing (though this may have been because he had half of Rampage’s spark, rather than a result of his Transmetal 2 nature) .
According to their toy packages and bios, the Transmetals 2 were all the results of Megatron's cloning experiments. In the show, the first Transmetal 2, Dinobot II, was created by Megatron in this way. This cloning experiment plot device also helped to explain the presence of Optimus Minor.
Unlike Transmetals, the Transmetals 2 did not have a third mode. Only the largest Transmetal 2 toys, Tigerhawk and Megatron, were designed to have more than two modes because they were planned mislabeled as the state-of-the-art Transmetal 2 as a marketing ploy. Megatron's vehicular mode was never featured in the TV show, and Tigerhawk's was abandoned entirely during production of the toy before being properly implemented.
Early on in the release of Transmetal 2 toys, the packaging used a Roman numeral "II", but a running change in the packaging was made to the Arabic number "2," which is now the prevalent spelling of the concept.
Beast Machines cartoon
When the Maximals encountered Megatron's virus, the Transmetals among them had a strange reaction. Rather than becoming instantly paralyzed, as apparently happened to the majority of Cybertronians exposed, they simply lost their Transmetallization. Primal, Cheetor, Rattrap, and Blackarachnia reverted to their pre-Transmetal beast modes (or, in Primal's case, the form he would have had if he hadn't been "born" a Transmetal). They were able to stay mobile, though glitching and amnesic, while Rhinox and Silverbolt immediately succumbed to paralysis. It seems that whatever Transmetal properties had protected Silverbolt from the Metal Hunter couldn't save him from the virus.