The Dawnstoke Citadel

Creatures cannot attack you or a planeswalker you control unless their controller pays 2 life for each attacking creature.
Whenever an opponent pays life, you may pay {p/r}{p/b}{x}{1} where X is the life they paid, if you do, create a 5/5 red dragon creature token with flying.
Dawnstoke may be the first line of defense, but it is a glorified torture chamber.