When a character touches a Size Beam, they will become bigger or smaller depending on the laser's color.
The Size Beams are usually fitted in corridors to shoot lasers down towards the ground. If the playable characters are caught in the beam, it will alter their size. The red Size Beams cause the playable character to become ⅔ of their original size. This will allow them to run through corridors otherwise too narrow to pass though. The blue Size Beams will cause the playable character to return to their default size.
Game appearances
Sonic the Hedgehog CD
In Sonic the Hedgehog CD, Size Beams appear in Metallic Madness Zone 2. In gameplay, the player finds them near the end of the Zone, where they will have to go through a big maze. Upon completing this "maze", the playable character will return to their normal size. Notably, when affected by a Size Beam, any power-ups the player is currently using, such as Power Sneakers and Invincible, will wear off. Also, entering the Time Warp after being affected by the Size Beam will cause the playable character to return to their normal size.
Sonic Mania
In Sonic Mania, and its expansion Sonic Mania Plus, Size Beams appear in Metallic Madness Zone Act 2. In gameplay, their function, appearance and features are basically the same as those in Sonic the Hedgehog CD. Size Beams are needed to progress through the Act, as they allow the player to enter sections that would otherwise be too small for them. Notably, similar to the size-resetting Time Warp error seen in Sonic the Hedgehog CD, when entering a Special Stage, Bonus Stage or Pinball Stage while shrunk by the Size Beam, the playable character will be returned to their normal size.
In the Sonic the Comic British comic series published by Fleetway Editions, a midget version of Sonic from a near future encouraged Sonic into a Size Beam to make him small as well. This was done so that Sonic would be able to infiltrate a machine in the Miracle Planet's past to disable it and prevent it from turning the planet into a mechanical wasteland.[1]
Trivia
In Sonic Mania, after being affected by the Size Beam, Super Sonic will have the appearance of a Sonic with golden fur. He will also keep Sonic's animations.
