Bubba

Bubba is the alternative boss of several levels related to water, similar to Unagi. It functions similarly to the enemy version in the main game, and is defeated using the Metal Cap.

Secret Aquarium
Works as listed above.

Aquarium Limbo
Works as listed above. This alternative boss fight is considered non-canon.

Bully Beach
Works as listed above.

Raging Rapids
Works as listed above.