Safehold Sentry

To use the toughness pump at all, this 2/2 has to be tapped already, and the only ordinary way a fresh body gets tapped is by attacking. That inverts how a defensive ability normally works: the +0/+2 is not for the blocker holding the line but for the attacker who has already committed. Swing in, then spend and the untap to grow to 2/4 for the turn, surviving a block that a vanilla 2/2 would lose. Sit it back untapped and the ability is dead, since there is nothing to untap; only an outside tapping effect lets it pump on defense. The price is deliberately heavy. Three mana plus the untap means the attack comes first and the toughness second, and you cannot keep the creature home as a blocker while paying for it. What you get is a body that pushes damage and then refuses to die in the combat math, forcing the opponent to ask whether trading with a 2/2 is really a trade once white mana sits open. Where the untap symbol elsewhere fuels mana or card draw, here it does something plainer: it converts a swing into staying power, reading the symbol for exactly what it depicts, a creature standing back up after it has already thrown itself forward.