|“||Dark balls of smoke and ash, Bos fly and hover in many of the different worlds. They don't pursue Kirby once he moves beyond their range.”|
|— Description • Kirby 64: The Crystal Shards Official Strategy Guide (Prima)|
Bos resemble small black spheres with rectangular white eyes, and they are surrounded by a blue aura.
Bos do not actively attack Kirby, but instead float around aimlessly. They are often found in groups, likely because they are mostly harmless and easily defeated.
- Two Bos appear in a mid-boss fight against a giant Pupa in Stage 3 of Shiver Star. If Bo is held above Kirby's head, it will immediately disappear and do nothing.
- Magoo, an enemy found at Neo Star's volcano, is a fiery version of Bo.
- In some dark stages in Kirby: Canvas Curse, tiny blob-like shadow creatures move around on the ground. They have round, purple bodies, silver eyes, and vaguely resemble a smaller version Bo.
- There's a similar enemy to Bo in The Legend of Zelda: Majora's Mask called Boe. They both look and act similarly, but unlike Bo, Boes leap onto Link.
- They look similar to Mariel, except they have no legs.