Sergeant Major Purple

Even though he is smart, Sergeant Purple (a.k.a. Ninja Murasaki) loses to Goku after a long, drawn out, somewhat farcical fight. He uses several ninja tricks to which Goku counters in his own kooky way. Even when he "split" into 5 Murasakis (the Murasakis were just 5 identical brothers with Sergeant Purple as the oldest), Goku was still able to defeat him. After the fight he tries to unleash Android 8 upon Goku, or he would destroy Android 8. Android 8 refuses, and Goku knocks out Purple before he could do anything. Murasaki eventually goes after Dr. Flappe and Android #8, but was presumably killed when Goku unintentionally tossed #8's bomb onto Murasaki's cheek in the anime only.