Will Ferrell and Rachel McAdams play Icelandic singing hopefuls in this over-egged musical comedy.

Balancing a hat on top of a hat, David Dobkin’s “Eurovision Song Contest: The Story of Fire Saga” tries to add even more humor to an event already legendary for its excesses and battiness. The result is a movie so eye-searingly extra it makes “Mamma Mia!” look bashful.

Seemingly operating on the belief that volume plus glitter equals comedy,