Witnessing the events of Megalomaniac, Gaster marvels at the abnormality of the timeline and wonders if he can utilize it to his advantage in order to escape the Void.
Sans is at his post in Waterfall when Frisk playfully wakes him up. Sans offers to go to Grillby's and Frisk agrees. Sans tries to teleport both of them to Grillby's, but Frisk is led astray when he finds an unfamiliar grey door in a corridor. Confused, he opens the door and enters, only to meet Gaster. Meanwhile, Sans arrives at Grillby's, planning to talk to Frisk about the previous timeline, but quickly realizes that Frisk is not with him.
As Frisk stares in fear, the door behind him shuts, locking him inside. Frisk attempts to RESET, but Gaster blocks Frisk's access to the buttons. Attempting to obtain Frisk's soul, Gaster attacks by using the Void substance in the room.
Frisk is able to dodge the slashes, but is unable to avoid the blast of a Gaster Blaster when it fires. However, Sans teleports inside just in time to deflect the blast with a bone.
Sans attempts to teleport himself and Frisk outside, but the ability fails to work while inside the room. Sans then uses a blaster to blow up the locked door, which allows him and Frisk to escape. However, this allows Gaster to escape as well. Upon leaving The Void, his body gains more of a form, and he can even use his Chroma abilities. Sans, realizing that the only way to defeat Gaster would be to absorb Frisk's soul, proposes the plan to Frisk, who immediately agrees. However, as Sans reaches to grab Frisk's soul, Gaster stabs him into a wall. Sans begins turning to dust as Gaster claims Frisk's soul.
However, Frisk is able to use his Determination to break free from Gaster's grasp, with his soul flying into Sans' hand. With the power of Frisk's soul, Sans is able to defeat Gaster with only some, if any, trouble. Gaster, saddened and defeated, tells Sans that he only wants to come back. Sans replies that what he's doing isn't the right way, but Gaster refuses to accept it and attacks Sans. However, before he is able to kill him, the latter sends bones shooting through Gaster's body, causing him to die. Sans then uses the RESET button and tells Frisk to take his time in the Ruins, as there’s something he needs to do.
Written by deleted on Jul 28, 2022