Portal 2's Turret Lullaby comic sheds light and lasers on the singing turrets

Valve keeps plenty of secrets from the world, locked away and tied down with live, stripped wires above a shallow pool of stale water, surrounded by a moat of baby hippopotamuses -- but this secret got out. Turret Lullaby is a six-page Portal 2 comic that explains the birth of the singing turrets. We don't want to give it away, but it involves a baby, a burglar and a lot of bullets.