sleep spreads like yawning.

Prerequisites: None

Benefit: You may use this feat to modify sleep or deep slumber or spells with similar effect. The spell level is not increased. You may cast sleep targeted on one creature. When this creature fails its save, the creature closest to the creature previously fallen asleep is also affected. This continues as long as there are creatures left in a 10 ft burst centered on the original target and as long as the HD limit of the spell is not reached.