J'onn mentions that the Hat's power comes from the 5th Dimension, a reference to Mr. Mxyzptlk.
Manchester Black slightly breaks the fourth wall when, at the end of a broadcast aimed at Supergirl, he says, "Time for a commercial break." And the act ends, going into an actual commercial break.
Brainy mentions his friend "Val," a reference to Val Armorr, aka the Karate Kid, a member of the Legion of Super-Heroes. He is a master of every form of martial arts to have been developed by the 31st century. The extent of his skill is so great that he can severely damage various types of hard material with a single blow, and was briefly able to hold his own against Superboy through use of what he called "Super Karate."
Rampotatek, aka The Hat, hailed from Japan and had access to a magic hat powered by a demon. He was recruited by Manchester Black to join his team of heroes known as The Elite. The Hat and the team's violent action lead them into conflict with Superman. He and the rest of the team were defeated and stripped of their powers.
The episode's title is a reference to the Superman story of the same name, published in Action Comics #775 (March 2001), that features the debut of Manchester Black and the Elite. The story name was based on the title of the Elvis Costello song What's So Funny About Peace, Love and Understanding.