The Hoop is a gimmick that appears in Sonic Dash 2: Sonic Boom. It is a large ring used for acceleration.
The Hoop is a ring larger than Knuckles that floats in midair. It is colored completely blue and glows with a cyan aura.
In gameplay, Hoops are located on the rails along Rail sections and Ener-Rails in the levels. When passing through a Hoop, the playable character is given an increase in speed, similar to a Boost Ring. However, the Hoop's speed boost only lasts for as long as the player is riding on its Rail/Ener-Rail section. When passing through a Hoop, the player also builds up one combo link for the player's score actions.
Some missions in Sonic Dash 2: Sonic Boom involves the player going through a certain number of Hoops in one run.