Horde

A horde is a massive group of normal Infected who fast attack at once, reminiscent of the movie 28 Days Later. They attack using their sheer number to attempt to overcome the Survivors. Hordes can occur due to a Survivor being splattered by a Boomer, setting off a car alarm, or just at seemingly random moments. An incoming horde is prefaced by a musical horn cue in the soundtrack followed by a burst of techno music that plays until the horde's numbers have been significantly reduced.