When Babyscale Bruiser enters, you may reveal a creature card from your hand. If you do, Babyscale Bruiser deals damage to target creature an opponent controls equal to the revealed card's power. That creature deals damage equal to its power to Babyscale Bruiser.
Put two +1/+1 counters on target creature. Untap that creature.
“Why did you save me? After the ravagers fell, you could have cut me down just as easily.” “War was never what I wanted, elf. Now do you finally believe me?” —Imisti and Queen Asamund
First strike Back-Alley Gnoll has lifelink as long as it's enchanted by a black Aura. Back-Alley Gnoll gets +2/+0 as long as it's enchanted by a red Aura.
Desecrate (When this creature enters, you may sacrifice an artifact or land.) When Back-Alley Vandal desecrates a permanent, put a +1/+1 counter on Back-Alley Vandal.
Mark (Whenever this creature attacks, mark target creature until end of turn.) Whenever Backalley Silencer deals combat damage to a player, destroy target marked creature.
Haste When Backdrop Artisan dies, audition for red. (Create a 1/1 Construct Actor creature token, a Warrior Role giving 3/2 and trample, or a Wizard Role giving 2/2 and prowess. Roles replace older ones.)
When Backstage Broken enters, create a 1/1 colorless Construct Actor creature token. Whenever a token you control leaves the battlefield, you gain 1 life.
The Unhinging Project was only meant as horror for audiences, but it broke performers in equal measure.
When Backwoods Cultivator enters, put a +1/+1 counter on target creature you control. When Backwoods Cultivator dies, proliferate. (You choose any number of permanents and/or players with counters on them, then give each another kind of a counter already there.)
Whenever you discard a card, exile that card from your graveyard. {2}, {T}: Draw a card, then discard a card. {4}, {T}, Sacrifice Bag of Holding: Return all cards exiled with Bag of Holding to their owner's hand.