The door and most of the room was covered by a black half sphere. It provoked immediate and loud cursing from the demons closest to the other side of the door, and seemed to stop them on their tracks. They should have already gotten in, but clearly nobody on the enemy side wanted to volunteer and go grope blindly for a door handle inside a blob of eldritch terrors. Whispers of the warlock's spell distorted the sounds from the other side as their tone calmed down. A few nerve wrecking moments went by. It got difficult to tell whether they were still waiting out there. For now they certainly weren't coming through the door.