Great Cannon

Great Cannon is a Decepticon from the Operation Combination portion of the Generation 1 continuity family.

Great Cannon is (most likely) the leader of the Battle Gaia team, which means he is (probably) the second-in-command to the Decepticon Scrash. He combines with his teammates to form the mighty Battle Gaia.

... look, they're not giving us a lot to work with here, okay?

Fiction

Operation Combination story pages

Great Cannon is never shown as an individual robot, only as the torso to Battle Gaia.

Toys

Operation Combination

• Battle Gaia (Multi-pack, 1992)

Japanese ID number: TF-10

Great Cannon is a redeco of Onslaught, transforming into a longnosed truck cab with extended trailer bed and a large double-barreled cannon. Using the Scramble City style of combination, he can form the torso to any combination of limbs. He was only available as part of the Battle Gaia giftset.

This mold was also used to make Mega-Octane.

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