These two Autobots are great friends, each possessing special powers that make them unique.
HOUND
Hound is an Autobot who knows how to have a good time. He loves the planet Earth, and is great friends with Spike Witwicky, who teaches him all he can about Earth. Secretly, Hound wants to be human!
Hound can transform into the likeness of an Earthen jeep. In both this mode and robot mode, Hound can project 3D holograms of any size or shape he can concieve. He has been seen to project these holograms over vast distances (Ref: "The Autobot Run").
Hound, along with Cliffjumper, was the first to discover the Decepticons' plans for Earth's energy. He conjured up a plan to decieve the Decepticons, but unfortunately, it failed, as a result of information recorded by the Decepticon spy, Ravage.
In the Earth year 2005, Hound arrived on Earth as part of the reinforcements Optimus Prime had assembled to combat the Decepticon attack on Autobot City. Hound was not seen again after the conflict, and is presumed deceased.
Mirage is the pacifist of the Autobots, who desired only to return home to Cybertron when the Autobots were stranded on Earth.
Mirage has the ability to transform into an Earthen racing car. In both this mode and robot mode, he is able to project a rectangle of energy around himself which renders him invisible to the naked optical sensor. In robot mode, Mirage can also create hologrammatic duplicates of himself.
Mirage played an important role in the defeat of the Decepticons' original plans to leave Earth. Using his invisibility powers, Mirage stowed away on board the Decepticon ship, Nemesis II, and sabotaged the controls, so it crashed back to Earth, into the Pacific ocean.
Mirage continued to serve loyally, despite allegations from Cliffjumper that he was a Decepticon spy (ref: "Traitor"), and was present at the Autobot City Massacre of 2005. He was not seen thereafter, and is presumed to have either been terminated in the conflict, or gone into retirement.