Attack Me Not; Take Some Pain

All creatures have vigilance. At the beginning of each player's end step, tap all untapped creatures that player controls that didn't attack this turn. This artifact deals damage to the player equal to the number of creatures tapped this way.

Flash Tapped creatures you control can block as though they were untapped.

Flying Creatures can't attack you.

Flying If noncombat damage would be dealt to you, prevent that damage. You gain life equal to the damage prevented this way. When Purity is put into a graveyard from anywhere, shuffle it into its owner's library.