Back for their first late-night TV appearance in who knows how long, Fall Out Boy made it memorable on Jimmy Kimmel Live with glow-in-the-dark skeleton costumes. It was a visual effect better suited to Halloween – or not, given that it's Fall Out Boy – as the band stormed through their new single, "My Songs Know What You Did in the Dark (Light Em Up)," under black lights on an otherwise darkened stage while the crowd clapped along in unison.