The Ringmaster is the main antagonist of the Betty Boop cartoon "Boop Oop A Doop".
He was the owner of a circus in which a 17 year old Betty performed, upon seeing her, however, he grew lustful and decided to force himself upon her (a common theme in these early cartoons).
The Ringmaster was very devious however as he sneaked behind stage and entered Betty's tent as she left the Big Top and began to fondle her, when she told him to stop he threatened to fire her and then outright began to molest the girl - when she fought back he be became physical.
Upon seeing Betty in danger however her circus clown friend confronted the Ringmaster and the two had a violent fight in which the Ringmaster easily beat the clown and went as far as stuffing him in a cannon and attempting to launch him out of the circus grounds.
Yet the clever clown hid in the cannon and waited for the Ringmaster to gloat over his victory before pouncing out and hitting him with a mallet, knocking the brute out cold.
It is presumed Betty and the clown later left the circus and despite his evil actions it is likely the Ringmaster remained the leader of the circus (though he may of been driven off by others if they learned of his actions).