The first origin given for Unicron was given in Season 3 of The Transformers cartoon, years before Simon Furman came up with Primus. In the cartoon, Unicron was created by Primacron, an ancient mad scientist of similar size and shape to a monkey, who built him to wipe the universe clean of life for him. Unicron rebelled against his creator and destroyed his assistant, but its essence survived, taking the form of the Matrix of Leadership. Its essence repelled Unicron, and he left to devour countless worlds elsewhere in the galaxy until he encountered the real Matrix during .