Vector Sigma

"I am Vector Sigma. Before Cybertron was, I was."

Vector Sigma, as seen in the G1 Series

Vector Sigma is an immense and incredibly powerful super computer which exists in certain G1-Universes. Specifically, it only appears in the G1 cartoon, and the series Beast Machines (where it also goes by the name "The Oracle"). (It was also referenced by Shockwave in the Dreamwave "War and Peace" comic.)

In the G1 cartoon, Vector Sigma could easily be considered a replacement for the god Primus in that series. It is a large, spherical computer located in the very heart of Cybertron which has the ability to bestow life upon Transformers.

Vector Sigma was revealed in the season 2, 2-Part episode The Key to Vector Sigma. In it, Megatron steals Vector Sigma's activation key from Alpha Trion and uses the computer to activate his recently built Stunticon Transformers. He then leaves Cybertron with the Key still in tow.

In retaliation, Optimus had the Aerialbots constructed. Alpha Trion sacrificed his body in order to activate Vector Sigma long enough for the new Autobots to come to life.

Vector Sigma, as seen in the Japanese Headmasters series.

Shortly thereafter, it was revealed that in addition to activating Vector Sigma, the Key has the bizarre ability to turn any organic matter it came in contact with into lifeless metal. Megatron attempted to use this power to drain the Earth of all its natural energy, but his plans were thwarted and the key destroyed

From Teletraan I: The Transformers Wiki, a Wikia wiki.