It begins late at night, with a figure – later revealed to be rapper 2 Chainz – walking away from a black van parked in a forest clearing.

Two women then exit the van, carrying various musical instruments belonging to Fall Out Boy, among them the band's guitars, a bass, drumsticks and various drums and cymbals, before tossing the items into the fire.

2 Chainz then uses a flamethrower to hasten the incineration process, while the women return to the van and open its rear doors, revealing four hooded, bound men implied to be Fall Out Boy themselves.

The camera then closes in on 2 Chainz's face as he holds up a match and stares at the band menacingly, ending the video.

Jon Dolan of Rolling Stone called the song "a big, goofy, stomp-along pop-metal anthem".

[16] Collin Brennan of Consequence of Sound felt that the song's hip hop-esque beat set "Light Em Up" apart from the band's earlier material.

[17] Commercially, "My Songs Know What You Did in the Dark (Light Em Up)" debuted on charts worldwide with success, reaching in the top five in the United Kingdom, charts the band has previously received success from with singles like "This Ain't a Scene, It's an Arms Race" and "Thnks fr th Mmrs".