The disappearing platforms are high-tech devices. Design-wise, they consist of two red bars with hover-engines below them. These bars are connected by a transparent plate.
In gameplay, disappearing platforms act as unstable platforms. They are normally placed in long rows, forming short bridges, but can also appear individually. When touched by a playable character, it will fade away after a second, and then reappear a moment later. Disappearing platforms are usually placed over pits or previous sections, meaning the player will get noticeably delayed if they fail to cross them in time. Since regular running is too slow, the player must use Sprint to cross disappearing platforms in time.
Sonic Boom: Shattered Crystal
The disappearing platforms made their debut in Sonic Boom: Shattered Crystal. In this game, their bars with hover-engines are red while their connecting plate is light blue.
Sonic Boom: Fire & Ice
In Sonic Boom: Fire & Ice, the disappearing platforms remain mostly the same design-wise, the only difference being their colors, which have changed from red and light blue to orange and blue (to match the game's central theme surrounding fire and ice).