Minomusis are small, cylinders-shaped Badniks with a mostly yellow surface, and a red and curved top and bottom. On top of their body they have a pair of black eyes and along their surface area they have two rows of spikes.
In Sonic the Hedgehog CD, Minomusis only appear in Wacky Workbench where they hide in the overhangs using threads they spin themselves. When the player approaches, they lower themselves down for a few seconds and sprout their spikes, then zip back into their hiding place to repeat their pattern.
In the Bad Future or sometimes in the present timeframe of the Rounds, Minomusis' bodies show signs of wear and tear. These Minomusis are incapable of sprouting any spikes at all. Like every Badnik in the game, the Minomusis are powered by Little Planet flower seeds which will pop out of them after being defeated.