The Rebels are alerted to our presence. Admiral Ozzel came out of lightspeed too close to the system. He is as clumsy as he is stupid!
~ Darth Vader criticizing Admiral Ozzel for his incompetence
Don't you know a kid always wins against two idiots?
~ Kevin mocking Harry and Marv.

Villains who are more likely to accidentally foil their own plots than the heroes they're fighting against, due to stupidity, bumbling, poor planning, cowardly behavior, carelessness, weak strength, equally more incompetent henchmen, or arrogance on their part.

Incompetent villains can also have schemes that are ultimately stupid, pointless or do little to cause chaos. Sometimes their attempts at evil blow up in their faces by either causing them great harm or even aiding the heroes; thus, these villains are not really much of a threat but they can occasionally be annoying. They are mostly used in comedies.

Since Incompetent villains are generally used in comedies and not much of a threat, they are rarely Purely Evil.