"Bub" is a nickname given to a number of blue short people who fire ineffective guns at Little Mario. There are two theories to what they're doing and how they got their name:
- The Mercenary theory says that these are ruthless mercenaries hired by a mysterious man with unknown motives, possibly a mob boss, to bring down Little Mario. The man who hired them is known only as "Bubs", which is where the term "Bub" for these mercenaries comes from.
- The Bored Kid theory says that these are just bored kids with BB guns who like causing mischief and happen to be in some places that Little Mario visits. In this case, "Bub" is a single-syllable pronunciation of BB.