Gremlin Hyperion is a blueGremlin who's caged in the Jungle Boat Ride. After Mickey goes through the top exit of the cave he went into after defeating the first Sweeper, Hyperion's cage is in an alcove a few platforms away from the bridge.
Hyperion will help Mickey at the end of the stage by activating one of the cranks that opens the doors and makes one of the Sweepers fall into the Thinner. If Mickey also freed Trigo, Habel, and Pinza, he, along with them, will repair the last platform allowing access to a Silver Pin.
His name is a reference to Hyperion, the street where Walt Disney lived during his early days as an animator. It could also be a reference to a restaurant of the same name in Disneyland Paris.
The PC files of Epic Mickey 2 show that Gremlin Hyperion is placed in Mean Street South.