Rings

"Gather to increase remaining time. They are also found in Item Boxes!"

- Sonic Mania's description manual about the Special Stage(s).

The rings are circular objects that appear in Sonic Mania Adventures as well as in the games. These items are used to either protect a user, or maybe activate their super state with the help of a number of 50 rings.

Sonic And Tails
Said items only appear once in this episode, when Sonic the Hedgehog was in a rush to fight off the drilling scientist after Robotnik caused a smoke cloud to happen in the middle of the forests of Angel Island. But when doing so, he stops and gets blown away by one of Eggman's drills, releasing the rings he once possessed.

Appearance
The rings are yellow and shiny rings that are collected around the island. They are based on wedding rings or solid brass rings, but instead float above ground level.

Trivia

 * When Sonic gets hit by Robotnik's machine, the sound of losing rings in the games can be heard for a split second.