A thick fog coalesces from nowhere, hiding your allies.

Daily   ✦     Primal, Zone
Standard Action      Area burst 1 within 10 squares

Effect: The burst creates a zone of lightly obscured squares that lasts until the end of your next turn.

Sustain Minor: The zone persists, and you can increase its size by 1 to a maximum of burst 5.

Published in Player's Handbook 2, page(s) 86.