Until Hasbro settled on the name Nemesis Prime, the name Scourge was used for Black and Teal repaints of Optimus Prime. Prior to that, Scourge was a character from the original Transformers TV show - his role was that of the lackey of the planet-sized Transformer, Unicron (and later, during the third season of the original series, the lackey of Galvatron).
Squeezed between those two was Transmetal 2 Scourge. A mix of colours and with a unique leg design (somewhat similar to the one used in Beast Machines Cheetor), Scourge is unique in that he is a Transformer I did not want, did not buy, and have anyway. (My brother and sister gave it as a gag gift because I always complained about how ugly it was).