Klingon
Klingons may look a lot like humans, but don't say that to their faces. They'll be insulted by the comparison to their enemies in the Federation, with whom the Klingon Empire shares a border.
Klingon soldiers wear stylish purple uniforms, and the men all have beards. They travel in powerful Warbird spacecraft equipped with cloaking technology.
Fiction
Star Trek vs. Transformers
The Klingons disagreed with the Federation on the status of Cygnus Seven, considering them to have no right to mine the dilithium on the planet. A crew under the command of Kuri attempted to attack the mine there, but a shot from their defenses disabled the Klingons' ship and they were forced to retreat to a nearby moon, where they found a city they assumed to have been built by the Federation. Their assumption was soon corrected when the true owners—the Decepticons—arrived. But this proved fortuitous, as Megatron shared Kuri's distaste for the humans and the Federation. With a mutual enemy, the two forces decided to form an alliance. Prime's Directive, Part One
