In an attempt to make an infinite energy source for the Underground, W.D. Gaster created The CORE. He had worked on this machine for a long, long time and was extremely proud of it. But this pride led to a disaster. He refused to recognize that The CORE had a mistake in it, running the supposed energy source anyway. Just a few moments later, The CORE exploded, causing tragedy and CORRUPTION in the entire Underground. Years later, a child falls into the corrupted caverns, forced to face the destruction that awaits them... Undertale created by Toby Fox Corruptiontale concept created by me