Unfortunately, a Superdelegate is not someone that the Avengers send to a political convention, because that would be kind of awesome. Instead, it’s an undemocratic phenomenon within the Democratic Party that is effectively keeping old school machine politics on life support.
If you don’t know who Dennis Prager is, then 1) I envy you and 2) you’re not alone. Prager is a conservative radio personality from a previous decade. He’s not as well known as he used to be because he operates at a disadvantage in today’s conservative media market. He’s not batshit crazy.