Capsule

Knuckles breaking an Egg Prison in IceCap Zone

A capsule (or egg prison) is an object that is found at the end of a zone. These ubiquitous containers are where Dr. Robotnik stores the Animal Friends he's captured. The capsule acts as a 'finish line' for the player in that once it is activated, the zone ends and the player's score is tallied. The animals are usually freed by jumping on a button at the top of the capsule, although in Sonic 2 (8-bit), which features a kind of floating egg prison, Sonic has to spin attack into the underside to open it.

Capsules appear at the end of every third act in Sonic 1 and end of every second act in Sonic 2, Sonic 3 & Knuckles and Sonic Advance. They are also found at the end of Action Stages in Sonic Adventure.

In Sonic & Knuckles's Flying Battery Zone, the Doctor's skyship houses a great number of egg prisons which can be popped open during the normal course of the level. Instead of captured animals, these pods can contain rings, badniks, or even a cunningly-disguised sub-boss. Other capsules are empty, or the button may act as a spring.

Gallery

Sonic 1 (16-bit), Green Hill Zone	Sonic 2 (16-bit), Aquatic Ruin Zone	Sonic 3 & Knuckles, IceCap Zone	Sonic Adventure DX, Final Egg

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Sonic 1 (8-bit), Bridge Zone	Sonic 2 (8-bit), Green Hills Zone