The Flash Duet

Buffy the Vampire Slayer's Once More with Feeling - the OG genre musical episode (c) Mondo Records

Duet was a musical crossover between two shows: The Flash and Supergirl . Barry dips Kara, both in 1930s evening wear, while a red cape-like banner and lightning dances around them. A theatre ,marque above them displays the Flash TV series title.

Fringe Brown Betty
Lucifer Another One Bites the Dust