Grievous

"Ah, Jedi...(cough, hack, wheeze)...where the fuck is my anti-cough medicine?"

- Grievous

Grievous was a snivelling coward who, despite completly PWNING EVRYTING in that clone wars cartoon, would run away from anything and everyone in the film. He also had a very bad cough just to show how pathetic he was, despite lacking a throat. However, when he changed into his alter-ego Darth Grievous, he kicked everyone's arse. Including yours.