Reign of Terror is the second studio album by American noise pop duo Sleigh Bells. The album was released on February 21, 2012 by Mom+Pop. Following the critical success of their debut album Treats, Sleigh Bells started writing new material for their next album while on tour for their debut album, and recorded it over the course of five months in 2011. While Treats used a mixture of guitars and beats that eschewed pop song structures for their overall sound, Reign of Terror emphasized more guitar sounds that follow structures with emotionally heavy lyrics.