Turns out Kendrick Lamar's performance on the last episode of The Colbert Report was even more special than first thought. The song the rapper performed wasn't from his recently released To Pimp a Butterfly; it hasn't even been recorded. Terrace Martin, who produced a handful of tracks on Lamar's latest LP, revealed to Complex that the Compton MC wrote the "Untitled" track just for his Colbert Report. set. "It don't even exist nowhere in the world," he said, "except on The Colbert Report." At least we'll always have video footage.