An asshole is less than a villain - not usually a schemer or a manipulator, no great personality and even with even less motivation. An asshole is someone who manages to get by simply by being a tremendous dick, sometimes for no reason, sometimes just because he's getting paid to be a dick by someone else. Assholes are quite simply obnoxious and indefatigably nasty.
So it should come as no surprise that the biggest asshole of the day is none other than:
Anyone who ever played Super Mario Brothers knows this asshole well. How frustrating: you're cruising along, stomping on mushroom things and kicking green turtles, and suddenly some dick on a flying cloud starts raining spiny death down from the sky. At least the King Koopa has some motivation: he wants to ravish Princess Peach, steal a kingdom, amass some flying gold coins. He's greedy for some reason, and even though he's a giant turtle dinosaur thing he wants a (moderately) human bride. Fair enough. But Lakitu is just a straight-up punk, pulling down a paycheck from the boss to drop exotic munitions on some fat Italian plumbers.
You know, if Lakitu had been around in the 60s he would probably have been delighted to drop thousands of gallons of napalm on the Viet-Cong. If he had been working for the Allied Command in World War II, he would have flown the inaugural bombing run on Dresden. As horrifying as war in general - and Mushroom Kingdom skirmishes in particular - may be, there is a special kind of terror involved in the act of dropping heavy ordinance from the skies onto hapless victims. Lakitu is, quite simply, an asshole and a dick of the highest magnitude: if there are ever war crimes tribunals in the Mushroom Kingdom, he'll be first on the docket.