Originates from the show BIG BANG THEORY. The Cylons are a fictional race of robots and the arch-enemies of the humans in the TV show Battlestar Galactica.
In the new series of Battlestar Galactica two forms of Cylons appear - metal, robotic "Centurions" and human-looking "Skin jobs". Although some of the Cylons evolved into a humanoid form, they are condescendingly commonly referred to as "toasters" by the humans.
Sheldon owns a limited-edition toaster that imprints the head of a Cylon Centurion onto the bread. He attempts to make enough Cylon toast "to destroy all the human toasts on a Battlestar known as Galactica" in The Cornhusker Vortex. sheldon is a character in BIG BANG THEORY.

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