Supergirl (2015)

S2E13 Mr. & Mrs. Mxyzptlk

Mr. Mxyzptlk, a mischievous imp, arrives on Earth and professes his love for Kara. She attempts to gently turn him down, believing he poses no real threat. However, he takes her rejection as a game and begins to unleash chaos across National City. Mon-El, familiar with creatures like Mxyzptlk from Daxam, realizes the danger he represents. This leads to a heated disagreement between him and Kara about how to deal with the imp, putting a strain on their relationship. Meanwhile, Alex and Maggie enjoy their first Valentine’s Day as a couple.