Grotesque Mutation

The +3 to power is the part that matters, and it is doing two jobs at once. As a combat trick it swings the math hard: a creature that would trade or die in a fair block can suddenly punch through and live. A 2/2 becomes a 5/3, which survives combat with another 2/2 and eats it outright, killing their blocker while your creature walks away. You still spend a card to do it, so that is a one-for-one on paper; the profit is that your board is bigger after the exchange than before. As a race-ender the lifelink rider does double duty, because the extra damage does not just close the gap; it widens your life total while it shrinks theirs, and it does so on every point of damage the creature deals, not just points that land on a player. A blocked attacker still deals its full power to whatever it faces, so all five (or seven) points feed the life gain regardless of the blocker's toughness. Two mana at instant speed can buy a fourteen-point life swing in the right combat, and that arithmetic is why a spell like this lives or dies on whether the deck can reliably connect the creature in the first place. The +1 to toughness is the quieter half of the design: enough to nudge a body out of a burn range or flip an even trade into a favorable one, but not so large that it wins toughness standoffs on its own. This is the black aggressive trick in its purest form, spending a card to keep a card alive and push damage, raw tempo bought at the cost of card economy, built for a deck that wants the game over before the trade math catches up.