You toss a green globe toward your enemies. It explodes, showering them with acid and creating a boiling pool of caustic stuff that moves at your command.

Daily   ✦     Acid, Arcane, Evocation, Implement, Zone
Standard Action      Area burst 2 within 20 squares

Target: Each creature in the burst

Attack: Intelligence vs. Reflex

Hit: 6d6 + Intelligence modifier acid damage.

Miss: Half damage.

Effect: The burst creates a zone of bubbling acid that lasts until the end of the encounter. Each creature that enters the zone or starts its turn there takes 10 acid damage (a creature can take this damage only once per turn). As a move action, you can move the zone up to 5 squares.
You can use the Bubbling Acid Attack power, using a square within the zone as the origin square.

Update (2/15/2012)
Changed in December 2011 updates.

You toss a green globe toward your enemies. It explodes, showering them with acid and creating a boiling pool of caustic stuff that moves at your command.

Daily ✦     Acid, Arcane, Evocation, Implement, Zone
Opportunity Action      Close burst 1

Requirement: The Bubbling Acid power must be active to use this power.

Trigger: A creature enters the zone or starts its turn there

Target: The triggering creature in the burst

Attack: Intelligence vs. Fortitude

Hit: The secondary target is blinded until the end of its current turn.

Published in Arcane Power, page(s) 113.