Boom Boom

Boom Boom (sometimes stylized as BOOM-BOOM) is a henchman of Bowser that Mario fights in each fortress in Super Mario Bros. 3, before the player fights a Koopaling in an airship. He is very easy to defeat; all Mario has to do is Jump on his head three times to eliminate him, or hit him with fireballs or hammers if he possessed the Fire Mario or Hammer Mario power ups. Boom Boom would begin by simply walking left and right towards Mario. After being hit, he would start to charge, jump, and in some cases, fly. After being defeated, he will release a ? Ball.

Whether Boom Boom is a true species or just a recurring single character is unclear, but there are at least two Boom Booms in existence, as a few extra levels in Super Mario Advance 4: Super Mario Bros. 3 will pit two Boom Booms against Mario simultaneously. However, Boom Boom may be only one character, with clones of himself. This is possible because the Super Mario Advance 4 manual refers to Boom Boom as singular in the description: "Boom Boom, the faithful servant of Bowser."

At least one Boom Boom appeared in Mario cartoon series The Adventures of Super Mario Bros. 3, where he was nothing more than a silent power house. Much like in the game, only one Boom Boom was ever seen at any given time.

In the Super Mario Bros. movie, there was a bar called the "Boom Boom Bar," which was featured with some prominence in the movie.

In the book in the Nintendo Adventure Books series Koopa Capers, there is am item called Boom Boom's Socks, which is a reference to Boom Boom.

Trivia

 * In Super Paper Mario, one of the Sammer Guys that can be fought is named Flailing Boom Boom, which is an apparent reference to Boom Boom and how he would flail his arms around in battle.