From Sonic Retro
Orb Switches are teleporters exclusive to the haunted levels of Sonic Heroes. These switches have 2 different functions in their levels. In Hang Castle and Robot Storm, they flip the teams upside down. However, Mystic Mansion is the only stage that will perform teleport the teams from one room to the other. A light will spread onto the screen once touched by one of the characters of the team. Once they've been transported by these switches, they cannot return to the area where they've left off if they try to touch the switch that already took effect in the previous area.
Due to graphical glitches present on the PlayStation 2 port, the light changes blending causing it to appear translucent brightening the screen at the white point; It will rarely turn opaque making the black edges visible.