Unlock Door

Choose a door within range. The DC to pick the lock or open the door decreases by 3d6 for the next 10 minutes. If this decreases it to 0, the door opens itself for you. You can cast this spell multiple times on the same door, but for each successive casting of this spell, the next casting of this spell reduces 1d6 less until the 10 minutes of the first casting is up.