The Phantom Ruby is a mysterious stone with great power that appears in Sonic Mania and Sonic Forces. According to the game's digital manual, the stone was found by Dr. Eggman on Angel Island due to a unique wave signature emanating in the atmosphere. Upon noticing that the gem had an unexplainable power, the scientist sent his elite group of Eggrobos to retrieve it. Upon being excavated, the power of the gem sends Sonic, Tails, Knuckles and the Eggrobos to Green Hill Zone and causes the Eggrobos to transform into the Hard-Boiled Heavies, loosening a few of their screws.
Throughout the game, Eggman takes the gemstone for himself, and uses it to displace the heroes at different places in space-time; a power similar to the Time Stones. By the time the heroes reach Titanic Monarch Zone, Eggman has mastered control of the gemstone and has used it to create portals around the fortress, and transformed the Hard-Boiled Heavies into "Phantom" versions of themselves.
If Sonic collects all the Chaos Emeralds and defeats the Phantom Egg, the Phantom Ruby sends him, Eggman and the Heavy King to Egg Reverie Zone, a mysterious pocket dimension created by the Ruby itself. Time and space are distorted within this pocket dimension, as the background is psychedelic and the timer in the HUD is malfunctioning. After Super Sonic defeats the Phantom King and the Klepto Mobile, the Phantom Ruby reacts with the Chaos Emeralds and opens a portal that transports Sonic to an unknown dimension.
|Items in the Sonic the Hedgehog Game Series|
|Collectibles||Ring | Red Star Ring | Emblem | Chaos Drives | Material|
|Power-ups||Shield (Water, Lightning, Fire, Gold) | Invincibility | Power Sneakers | Power Core | Light Cores|
|Level Objects||Monitor | Spring | Spikes | Checkpoint | Time Warp Plate | Signpost | Goal Ring | Giant Ring | Capsule | Button | Bumper | Speed Booster | Chao Container|
|Powerful Items||Chaos Emeralds | Super Emeralds | Master Emerald | Time Stones | Chaos Rings | Precioustone | Sol Emeralds | Jeweled Scepter | World Rings | Excalibur | Phantom Ruby|
|Weapons||Piko Piko Hammer | Chaos Energy Cannon | Caliburn|
|Devices||Remote Robot | Combi Confiner | Mother Computer | Arks of the Cosmos | Miles Electric|
|Other||Chili Dog | Scepter of Darkness | Nega's Camera | Cacophonic Conch|