Cobra

Cobra is a ruthless terrorist organization determined to rule the world!

They sometimes rebuild Transformers.

Marvel Comics

G.I. Joe And The Transformers

Cobra manipulated Senator Barbara Larkin, using her to push through the development of Power Station Alpha so that they could then steal it for their own purposes. Things went awry when the Decepticons decided they wanted it for their own, but an alliance was soon formed... and broken, when Cobra learned the Decepticons planned to use Alpha to destroy the world.

Operatives involved in this mission included Baroness, Buzzer, Cobra Commander, Destro, Dr. Mindbender, Serpentor, Torch, Ripper, Zarana, and Zartan.

G.I. Joe Starring Snake-Eyes And The Transformers

In the midst of a scheme by Cobra Commander to bring new glory to his organization, the reconfigurable Silent Castle he had sieged from Destro was put into a state of constant metamorphosis. This caught the attention of a heavily-damaged Megatron, who flew to Trans-Carpathia from Canada and was enraged to discover a non-sentient piece of architecture instead of another Transformer.

This confrontation eventually led to an agreement between Megatron and Cobra whereby Megatron would receive a new, more powerful body (designed by Dr. Biggles-Jones) in exchange for the technologies of the downed-but-functional Autobot Ark.

Cobra helicopters led Megatron and the unearthed Ark from Canada to the Cobra-controlled town of Millville, New York, where its brainwashed denizens began to unload the spacecraft. Their operation was discovered by the G.I. Joe team, who Megatron was vocally uninterested in battling.

Not too long afterwards, a group of Autobots (Brawn, Chase, Hot Spot, Override, Skydive, and Steeljaw) arrived and battled Megatron in Millville, causing considerable damage to Cobra's property holdings and destroying any vestiges of town's use as a secret base.

As the situation continued to degrade, Cobra Commander ordered an evacuation of the town's assets and personnel from a position near the Ark. Megatron then arrived, and having captured Dr. Biggles-Jones, abruptly disregarded his previous agreement with Cobra Commander. He took the Ark for himself and blasted off, much to Cobra Commander's extreme annoyance.

In-transit, Megatron voiced that he had transferred a virus that had been implanted in his new body by Dr. Biggles-Jones to the Cybertronian technology in Cobra's possession, which would render it inoperable.

Operatives involved in this mission included Cobra Commander, Dice, Dr. Mindbender, Road Pig, Slice, and Zarana.

Transformers Generation 2

Following Megatron's departure in the Ark, a convoy of Cobra vehicles departed Millville, safeguarding a transport containing the (unknowingly infected) Cybertronian technology they had acquired.

The convoy was assaulted by Autobot Hot Spot, who feared the havoc that could be created by the alien technology in Cobra's hands. As Cobra soldiers prepared to retaliate against him, they were cut down by Snake-Eyes and General Hawk, which gave Hot Spot the opportunity to destroy the transport.

Surrounded and heavily damaged, Hot Spot destroyed himself rather than be captured and dissected by Cobra's technicians for knowledge.

Operatives involved in this mission included Cobra Commander.

Devil's Due

G.I. Joe/Transformers

Cobra discovered the Ark and turned the Transformers within it into remote-controlled war machines. They were used to strike at Washington, D.C. and the SPS Research Facility.

Operatives involved in this mission included Baroness, Cobra Commander, Destro, Dr. Mindbender, Firefly, Major Bludd, Storm Shadow, and Zartan.

Two years later, an attempt by Cobra to seize control of Teletran-3 resulted in several Transformers being sent to various eras in Earth's history, threatening to catastrophically alter the timestream. Cobra and G.I.Joe were forced to work together to neutralize the threat.

Operatives involved in this mission included Baroness, Buzzer, Cobra Commander, Destro, Dr. Mindbender, Percy, Ripper, Storm Shadow, Tomax, Torch, Xamot, and Zartan.

From Teletraan I: The Transformers Wiki, a Wikia wiki.