Autobot X (G1)
Autobot X was a Autobot constructed Transformer that was built from various parts at Autobot Headquarters on Earth.
The various parts prevented Autobot X from possessing an alternate transformation mode, however, this gave it the ability to make use of various Autobot special powers as well as various weapons.
Fiction
Generation 1 cartoon
Sparkplug Witwicky created Autobot X out of spare Autobot parts. During the initial test run, Autobot X instantly starts to destroy Wheeljacks workshop. Unable to control him, Ironhide and Trailbreaker are able to bring Autobot X under control. Optimus Prime orders that he is too dangerous to be reactivated, but Sparkplug begs that he be able to fix Autobot X’s bugs. Wheeljack volunteers himself and Ratchet to help, in hopes that Autobot X body can be a temporary home for any Autobot mind who’s own body is in need of serious repair. Optimus Prime approves.
At a Rocket base test site, Spike is severely injured by Megatron. The only way to save Spike is to transfer his mind, at the recommendation of the doctors at Metro Hospital, from his body. Sparkplug and Wheeljack then transfer Spikes mind into Autobot X. Autobot X and Spikes minds meld to form Autobot Spike. Once Spikes body was healed, Wheeljack and Sparkplug transfer Spikes mind back into his own body. Autobot X was never reactivated.Autobot Spike

