For those who haven’t seen the episode yet, this is your spoiler warning.
A quick recap
As previously reported by the Deseret News, Episode 7’s big twist occurs near the end of its runtime when a side character named Agnes (played by Katheryn Hahn) reveals her true identity as a powerful, malicious witch named Agatha Harkness.
According to Nerdist, the name Harkness should found familiar to comic book readers as the character was first introduced to the Marvel canon in 1970. In “WandaVision” it is revealed, with a little help from aforementioned jingle, that Harkness has been has been secretly stirring up trouble in the protagonists’ household since the very first episode.
About the song
The tune is called “Agatha All Along” and according to CNN, it went viral after it premiered Feb. 19. It was composed by Kristen Anderson-Lopez and Robert Lopez, the musical minds behind “Frozen’s” award-winning ballad “Let It Go,” while Hahn provided the vocals for the track. The song, which Variety refers to as a “‘Munsters’ channeling ditty,” has a one minute and two second runtime and is listed as track No. 2 on the “WandaVision: Episode 7” original soundtrack.
The Verge reports the song is now available to stream on both Spotify and Apple Music. You can also listen to it here: