Dormammu creates a pool of fire on the ground in front of him that lasts for 180 frames, or about 6 seconds. Only one Flame Carpet per player can be in play at a time, and cannot be special or hyper cancelled. In UMvC3, Flame Carpet disappears if Dormammu gets hit, making it far less effective, but Flame Carpet is still an essential part of Dormammu's gameplan.