UNDERTALE/Gaster

Overview
Like Chara and Frisk, Gaster is one of the most speculated characters in the game. He was intended to go in the game, but was removed for unknown reasons. The only reason we know he exists is the Gaster Blaster (Sans's special weapon), the mystery man sprite that appears in a certain room in the waterfall (only appears when fun value is at a certain number), and his followers that appear in Hotland (also appears at certain fun values). The river man also mentions him.

Appearance
His "mystery man" sprite is seen wearing a black robe and having white skin. He is also seen having a cracked face. There is another sprite speculated to be Gaster that can be seen elsewhere in the waterfall; it looks like a stretched-out version of Napstablook without the face and with black areas on it.

Personality
*redacted*

In the Game
He is mainly only seen in the waterfall and mentioned by his followers in Hotland. He is presumably mentioned by the river man when he says "Tra la la, beware the man who speaks his hands."

Trivia

 * Gaster is the most speculated character in the game.
 * He is said to be the father of Sans and Papyrus.
 * This would mean that he is the creator of the Gaster Blaster as well as the CORE.
 * There is a machine is Sans workshop that was never meant to be fixed, as Toby Fox said.
 * This could be the machine that caused Gaster to disappear, and that he is supposed to stay shattered. FOREVER.