A spin-off of The Sonic the Hedgehog Continuity Thread of Love and Timelines: Headcanons are common in that thread due to the current uncertainty of the canon at present, as well as needing them to patch continuity issues. This is to separate them out so the continuity thread can better focus on said continuity, while allowing us to discuss the headcanons we have. I'll start with a few of the headcanons I've mentioned, but can catalogue here for discussion should it be wanted: Knuckles may have been Tikal'd by the Master Emerald, dragged from a past point in time to better assist the Master Emerald in the present against the Death Egg. No longer really consider it though, but catalogued. Sonic Shuffle leads into Sonic Advance, as the former ends with the four characters of the latter running along a beach, which it opens with. The first Sonic the Hedgehog game alternates between the two version's Zones, so after passing through Marble Zone, Sonic crosses the Bridge Zone to reach Scrap Brain Zone, then enters the Jungle Zone to enter the Labyrinth Zone. Eggman is a nickname derived from how Robotnik initially introduced himself to Sonic: Extraordinarily Gifted Gentleman. The Phantom Ruby of Sonic Forces is a copy of the original found in Sonic Mania, which was otherwise lost. The Classic Sonic of Sonic Forces is subsequently actually a Phantom like Zavok and Metal Sonic, 'born' from Sonic's being in the original Phantom Ruby's illusions when Robotnik scanned it, and the power of friendship 'summoning' him when Tails needed him. The end of Sonic Mania instead leads straight to Encore Mode, no Sonic Forces for Sonic yet. Sonic used Chaos Control at the end of Sonic Adventure 2 to repair the damaged Moon, which also distracted him away from Shadow, which is why Sonic was not able to catch Shadow as he fell. The second moon sometimes seen in games like Sonic Riders is the back of the ARK, still in orbit around the Earth. Possibly made canon by Sonic Channel, but best kept here for now. There's multiple Hidden Palaces: each contains an Emerald Pillar that acts as a relay for the Master Emerald, alongside one in the Emerald Altar, spreading the Master's power. Most are found on Angel Island, but there's a few elsewhere: one on Westside Island under the Mystic Cave Zone and one on the island of Chaotix. So long as the Master Emerald is in contact with one of these, the others distribute the energy. Most societies were able to access the Master Emerald's power through these emerald pillars, but they ended up buried after the Echidna attacked and arose Perfect Chaos. South Island's reliance on the Chaos Emeralds during Sonic Chaos is due to damage sustained from Robotnik: the Emeralds are acting as stitches and repairing the island. When Robotnik took one and scattered the rest, it was like removing stitches early and South Island began to sink. Sonic returned them to the island, and when it finished being restored by the Emeralds, they scattered, leading to Sonic Drift and Sonic Triple Trouble. During the Classic Era, Sonic would often keep a hold of one of the seven Chaos Emerald and collect the other six when needed, which is why we only see the six collected in most Game Gear games. This stopped when Robotnik shot him and caused the Chaos Emerald to break into pieces, during Sonic Blast. The town in Ice Cap Zone of Sonic Adventure is not actually on Angel Island, instead it was a town that had an island drop right in front of it, coincidentally lining up with the mountaintops of snow that we consider as Ice Cap Zone. The events of Perfect Chaos were depicted on the roof of the Emerald Altar, which is the mural of the Ancient Dragon Egg that Knuckles refers to during Sonic the Hedgehog 3. The depiction was destroyed when the Death Egg crashed into Angel Island. Vector was fully aware of Robotnik during Sonic Heroes from the events of Chaotix, but was deliberately taunting him by not recognising him to get a reaction out of the scientist in their first combat, due to suspicions of their client. When he didn't respond as he should've, it confirmed Vector's suspicions were valid. Charmy is just an idiot, while Espio clicked but had already reacted with familiarity, so served to 'explain' to Vector who Robotnik was to continue the guise. The powerups that Tails collects in the prequel Tails' Adventure, if considered as in-universe and not game trinkets, are Echidna relics depicting the cast, akin to the Hydrocity Zone statues of Sonic in Sonic the Hedgehog 3. Mobius of Sonic the Hedgehog Spinball is a planet found in Subspace, where Fang the Sniper hails from. The Emeralds of Sonic the Hedgehog Spinball are Conduit Emeralds, not Chaos Emeralds, which are, as the name suggests, acting as conduits for the Chaos Emerald's power throughout Mt. Mobius. One is used later in Sonic the Fighters to focus all seven Chaos Emeralds into one point for the rocket, hence the mysterious eighth Emerald of that game. Shadow is legally Shadow Robotnik. He can also legally go by Shadow Doom, Shadow Doom-Robotnik or Shadow Robotnik-Doom, but doesn't really like to talk about his family situation so just goes by Shadow the Hedgehog. A common one, but the cast have aged over the events. Using the Adventure Era as a base, where Sonic is 15, minus 3-4 years for the Classic Era, and plus 2-3 for the Wisp Era (Current Era until Sonic Frontiers releases). My major and favourite one: Metal Sonic is developed from Good Future Technology found on the Little Planet, but due to going to the past and attacking, Robotnik and Metal Sonic are now chronolocked into the Bad Future. Basically, no matter what, Robotnik and Metal Sonic will only ever see the Bad Future, even if Sonic creates a Good Future. As a result, Robotnik can not build another one, resulting in the Mecha Sonic line to try and built a suitable copy of Metal Sonic with modern technology and developments. Related to the above, Metal Sonic has a nanite repair system, that repaired him over time after his defeat in Sonic the Hedgehog CD and allowed Robotnik to recover him even while missing some CPUs during Sonic the Hedgehog 4 - Episode Metal. This was later soft-hacked by him to give him his liquid metal properties in Sonic Heroes. Alright, I think that covers my headcanons from the Continuity Thread. Anyone got any more?