If bright colors are nature's way of saying "do not touch", then nature's got nothin' on Sunstorm (サンストーム Sansutōmu). Come too close, and circuits will short, steel housing will begin to melt, and psyches will break as the mind struggles to comprehend. Science would explain that his body is aflame in radiation, but Sunstorm has different ideas.
Sometimes, Sunstorm merely believes he is secretly some kind of supernatural being, keeping his comrades away with his odd behavior. At other times, he thinks that he is the living embodiment of the Will of Primus, placed by the divine in this universe to deal righteous judgment on the blasphemous. Occasionally, he just hovers silently in the background and shoots at things.
Such is life.
His alt-mode is a Modified F-15 Eagle.