While a district court may convert a motion to dismiss into a summary judgment motion in the parties submit evidence in support of the motion, FRCP 12(d), the district court cannot sua sponte convert a summary judgment motion into a motion to dismiss. Here, defendant didn’t move to dismiss for lack of lack of Article III standing but raised the issue in response to plaintiff’s summary judgment motion. At that stage of the case, the district court could not sua sponte dismiss on the ground that the complaint failed to allege Article III standing properly, but instead had to consider the evidence that the plaintiff had submitted to establish his standing to sue.