When Chara rampaged through his timeline, Sans injected himself with determination in order to gain the power to stop them, resulting in the ability to see the Reset screen. Now he faced Chara over and over in battle with hope, but soon realized that every time Chara reset, he was becoming more predictable. Eventually Chara would defeat him, but in the middle of him turning to dust, he left the timeline completely. This caused his body to be covered in glitches and holes, as well as only holding a 9th of a soul. The new timeline’s Sans kept experiencing nightmares of a genocide run, eventually meeting the human and confronting them at Grillby’s about the dreams he was having. He discovered this human was Chara, who he erased from the timeline only to be pulled out of his to meet the previous Sans who calls himself “GenoSans”. There he learns about everything that is going on; . now he must figure out a way to stop Chara before his timeline is destroyed and the world ended for good. Stolen from here: http://undertaleau.tumblr.com/post/138198742109/aftertale-au Heya. Maybe press the space bar, whatever that means.
I made the sprite using paint. Here's the music: https://www.youtube.com/watch?v=0Obaf19OUro