Board Thread:Questions and Answers/@comment-24219388-20160512004529

W.D. Gaster was from a timeline where the monsters beat the humans in the war, and the humans were sealed underground. W.D. Gaster met a woman (Arial lol), fell in love, and eventually had a baby named Sans. Gaster was also a science enthusiest, and Sans enjoyed learning science with his dad. When Sans was around 14, him and his dad were busy studying different timelines. They eventually started working on a machine that would travel to a separate timeline. Around that time, Gaster and Arial had Papyrus. One day, probably when Papyrus was 3, and Sans was around 17, the machine was complete. Gaster, Papyrus, and Sans where the first people to test, as sort of a father-son bonding time. They arrived in Snowdin, but a critical problem happened. The machine malfuctioned in the test run and it broke. Gaster and Sans eventually started building a house in Snowdin, with Gaster's lab in the back. Gaster puts the machine behind a curtain in that room. One day, Asgore was looking for a new royal scientist after the previous one died in a failed experiment. Gaster applied, and he passed the test. Gaster made all kinds of inventions, including the Gaster Blaster and the CORE. One day, when Gaster was working in the CORE, and he accidentally slipped on some metal and fell into his creation. Sans was left to raise Papyrus to adulthood. Sans also took over his father's lab, with a one of his dad's royal scientist badge, and a San's painting of him, his dad, his mom, and his childhood friend, with writing on the bottom that says "Don't Forget". Also, this explains why Sans knows what the sun is. 