Octoboo

Octoboos are an undead variant of Octoombas appearing in Super Mario Galaxy 2. They appear in the Haunty Halls Galaxy and Boo Moon Galaxy as regular enemies. In the first level "A Glimmer of Bulb Berry", they are the first enemies to be encountered and they can be found in groups while encircling a select area. In the second level "Sneaking Down the Creepy Corridor", Boo Mario has to avoid these enemies in order to progress through the area. Octoboos resemble white, legless Octoombas with ghostly tails. They primarily move around by floating in a set area and they can also become transparent when the player uses a Star Spin on them or a tongue grab from Yoshi, thus avoiding any attack.

Trivia

 * Octoboos can be heard to make small Octoomba sounds if Mario or Luigi is close to them.