At this point, it’s pretty expected for every big indie rock type to make the late-night rounds whenever a new record drops. But there’s still a transgressive charge to seeing El-P, patron saint of New York noise-rap, stopping by to see fellow redhead David Letterman on network TV last night. El brought Islands frontman Nick Diamonds along to do “Stay Down,” a song from his masterful new album Cancer For Cure. Diamonds guested on vocals and Roland synth, and El’s live band (including trombone!) did excellent work at recreating the headblown clusterbomb beat, with El himself helping out on keyboard during the song-closing psych freakout. Letterman, understandably enough, looked a bit baffled, but Paul Shaffer “loved it.” Watch it below.