Attacking players vs attacking planeswalkers

There are many cards that affect attacking creatures, and either limit what they can attack or assess a cost when they do. For example, requires that the controller of any creature attacking the controller of the Prison to pay 2 generic mana. However, Ghostly Prison does not affect any creature that attacks a planeswalker controlled by this same player. This is mostly because Ghostly Prison was printed before planesalkers were introduced. Compare this to . Norn's Annex specific creates a restriction

Read more.