Lakithunder

Lakithunder is the World 7 boss in New Super Mario Bros. He is a Dark Lakitu with sunglasses and rides a dark cloud; he is a member of the Koopa Troop. As the name implies, he can shoot lightning directly under him, and also throw Spinies. Mario must Jump on Lakithunder's head three times, when he swoops down low, to defeat him. Lakithunder, however, does not need to be defeated, as World 7 is optional.

Trivia

 * Lakithunder bears a large resemblance to Lakilester from Paper Mario.
 * Lakithunder was most likely the person who attacked Peach's Castle at the beginning of the game.
 * Because of the possibility he attacked Peach's castle, and he was the closest boss to World 8 (numerically), he could possibly be an assistant of Bowser or Bowser Jr.