Capsule

Capsules(カプセル Kapuseru?) or Prison Eggs, are large metal containment units used and created by Dr.Eggman. The purpose of these units is to contain all the captive animals and Little Planet Flowers, which is used for powering his Badniks. Capsules first appeared in Sonic the Hedgehog(game) and has transcended into the majority of other titles as a stable object. In Sonic 3 & Knuckles, numerous capsules can be found in Flying Battery Zone that also contain rings while others are able to be used as a Spring. At the end of the zone's first Act, there is even a sub-boss with the appearance of a capsule with eyes and large spiked balls called, Gapsule. In Sandopolis, there is one in the second Act that releases ghosts called, Hyudoros to harm the character(s).

Wisp Capsules
Wisp Capsules are the variant of Capsules exclusive to Sonic Colors also created by Dr.Eggman. These are specifically used to capture Wisp.