W.D. Gaster

Dr. W.D. Gaster is a fictional character from the 2015 video game Undertale, created by game developer Toby Fox. In the game's lore, Gaster was Alphys's predecessor as the Royal Scientist for the Underground's kingdom of monsters. He was said to have created the Core in Hotland, which converts geothermal energy into magical electricity for use in the underground. However, he one day vanished without a trace, and was said to have been "shattered across time and space". He cannot normally be encountered in the game, and is never discussed directly as part of the game's main narrative. Players can only encounter events related to Gaster under a specific RNG condition called the "fun" value or by modifying the game files. A sprite from one of these events, internally named "Mystery Man", is generally used by fans to portray Gaster, though the sprite's connection to the character is not yet fully confirmed. The existence and nature of Gaster has been the subject of speculation among both fans and critics. Multiple theories exist about him, including ones suggesting that he is related to Sans and Papyrus, and that he is a major force behind the story of Undertale's parallel game Deltarune, due to multiple reasons, such as the game featuring allusions to his theme and his hidden "Entry Number Seventeen" (stylized in all caps and the Wingdings font) from Undertale. It has also been argued that his first two initials are a reference to Wingdings, due to his aforementioned entry using the font. This indicates that he could possibly be a skeleton like Sans and Papyrus, who are also named after fonts; Comic Sans and Papyrus respectively.