Vinetale AU
Sans and Gaster have the same soul. One of Gaster's experiments ended in failure and subsequent great destruction. Fortunately, Sans was nearby at that time and, in order to save his father, he gave him a piece of his soul.

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seen from South Korea
seen from South Korea

seen from Brazil
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seen from Türkiye
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Vinetale AU
Sans and Gaster have the same soul. One of Gaster's experiments ended in failure and subsequent great destruction. Fortunately, Sans was nearby at that time and, in order to save his father, he gave him a piece of his soul.
Here’s W.D. Gaster for Vinetale/Vinetrail!~ (Name of AU is a WIP atm~)
Gaster (And Alphys among others) created Flowey, and ended up creating an entity that corrupts whatever it touches through the use of magic. In Gaster’s case, Flowey killed him and revived him with Vine Magic, making him the First of the Corrupted Monsters. (WIP name too)
Flowey doesn’t even remember who they were as Asriel, they are mindless, and more or less act like a hive mind for those who are corrupted, linking them all together through their vines that are in each host.
Once Gaster was Corrupted, he was wrapped in vines and a flower was chosen for him and placed over his chest. This flower, along with the vines, enhances magical abilities and lifespan tenfold.
Quick ref
Quite quickly he gained popularity among people and began touring. Rust often grumbles about this because it means they rarely see each other with MTT (They have a platonic love, nothing more) Mettaton sends Rust cards and new posters with his face and various words of encouragement and love on the back. When they are both alone, they withdraw as much as possible from everyone and spend many hours talking and watching the stars. MTT even gives personal "concerts". Mettaton sometimes jokes about Rust's skeletal appearance, which he greatly enjoys. And in the company of Sans and his brother Papyrus, the skull eventually explodes.
Vine Toriel
She is sometimes called the Silver Queen. Behind her there is always a trail of flowers, similar to developing smoke.
Feeling all the hatred for people and losing all hope of salvation from the underground, the monsters, contrary to all the promises of King Asgore, decided to take their fate into their own hands. Some even stopped considering Asgore their king. Monsters began to hunt people trapped in the ruins in order to get their souls and leave the underground. Rust took possession of one of the human souls, but the man himself gave it to him. They were good friends, Rust protected him like a brother, and the child only wanted the skeleton to be so happy. Horns and claws appeared as a result of the absorption of a human soul. And I decided to imagine what Rust would look like if he absorbed more souls.
Guys omg..
Things happened and I want your votes:
Should my Undertale AU be named Vinetale-
Or Vinetrail?