Big Top is an alien from the Marvel portion of the Generation 1 continuity family.

Bring me Solo and the Wookiee. They will all suffer for this outrage.

Mr. Big Top runs the Cosmic Carnival. The green tentacled slug-like circusmaster likes to smoke cigars, leak slime, and call Goldbug "Buggo".

A good number of the carnival's attractions appear to be there on less than consensual circumstances, which is an environment that Big Top personally cultivates. He swindles unsuspecting patrons into binding contracts, leaving them caged indefinitely.

He puts on an air of grandfatherly showmanship, but he's as monstrous inside as his slimy appearance would suggest.

Fiction

Marvel The Transformers comics

Mr. Big Top had run the Cosmic Carnival as long as anyone could remember. A number of years ago, he abducted a human outcast named Berko, and promoted him to boss of the sideshow when the grousing bald man began to do tricks for the carnival's patrons. Later, Big Top signed on a group of human children and the Autobot Sky Lynx when the latter brought the children on board without any form of payment.

Sky Lynx's resulting fame caught the attention of Optimus Prime and a group of traveling Autobots. When the Autobots boarded and asked if Sky Lynx and the children could be released, Mr. Big Top cited their binding contracts, but gave Optimus Prime and his companion Goldbug free passes in an attempt to placate them. Optimus and Goldbug tried to leave with Sky Lynx and the children anyway, and with the help of Berko, they escaped, leaving Big Top trapped in one of his own sideshow cages.

This did not make him happy, but the patrons seemed to think he looked kinda neat, if ugly. The Cosmic Carnival