Give No Ground

The +6 toughness is doing the heavy lifting here, not the +2 power. This is a fog disguised as a combat trick: the multi-block clause turns a single creature into a wall against an entire attacking army, and the toughness bump is sized so that the blocker survives soaking up several attackers at once. The math is the point. A defender stacking six toughness can eat three or four small attackers and live, eating the alpha strike that a wide aggressive board was counting on closing the game with. Where a conventional combat trick saves one blocker in one exchange, this one rewrites the entire combat step from the defending side, collapsing the attacker's spread-damage plan into a single ambush. The instant speed is what makes the bluff matter: held up across the attack step, it threatens to negate a whole turn's worth of swing, which forces the aggressor to commit fewer creatures or hold back entirely. Four mana for what amounts to a one-card combat reset is a steep rate against a single attacker, and that is the constraint that keeps it honest; it pays off only when the board is wide enough that the multi-block clause does real work, which is precisely the spot where a defensive white deck most needs to survive a turn.