If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Exile target creature. Its controller gains life equal to its power.

As an additional cost to cast this spell, discard a card. Draw two cards.

Exile the top card of your library. You may put that card into your hand unless it has the same name as another card exiled this way. Repeat this process until you put a card into your hand or you exile two cards with the same name, whichever comes first.

Hideaway 4 (When this land enters, look at the top four cards of your library, exile one face down, then put the rest on the bottom in a random order.) This land enters tapped. {T}: Add {W}. {W}, {T}: You may play the exiled card without paying its mana cost if you attacked with three or more creatures this turn.

Until your next turn, your life total can't change and you gain protection from everything. All permanents you control phase out. (While they're phased out, they're treated as though they don't exist. They phase in before you untap during your untap step.) Exile Teferi's Protection.

Add {B}{B}{B}.