Cactus Balls resemble spherical green cactuses with lines of spiky spines and a pink flower on top. They also have a face on the front which consists of two purple eyes and a mouth with two fangs. They display a disinterested expression on their face.
In the Wii U/PC version, Cactus Balls appear in Desert Ruins Zone 1 and 4, as well as Sky Road Zone 4. They come in two sizes: giant and tiny. In Desert Ruins, the giant ones appear in Zone 1 and 4 where they roll around in groups, and the smaller ones appear in Zone 4, where they bounce left and right in slow patterns. In Sky Road Zone 4, giant Cactus Balls serve as obstacles during the sand sliding sections, where they rise from the sand behind Sonic and roll after him. The player is unable to defeat them by any means.
In the Nintendo 3DS version of the game, giant Cactus Balls appear in Desert Ruins Zone 1 and 3. Like in the Wii U/PC version, Cactus Balls either remain stationary or roll back and forth in linear patterns. Cactus Balls are invulnerable to regular attacks, but they can be reduced to rubble by the Indigo Asteroid and be used to enlarge the Asteroid Ring.
- In the game's files, this enemy is simply named "Cactus Balls".