Bub is a small green dragon and protagonist of the Bubble Bobble series. His special ability is spitting bubbles and turn enemies into bubbles. In Mushroom Kingdom Fusion, Bub appears in the level Bubble Pipes and plays an important role in helping the player navigate through the level as his bubbles can turn enemies into bubble platforms that the player can jump up to reach new places.
Bub's appearance differs depending on what character the player has selected: