Bar the Door

The defensive cousin of the white pump spell, and a study in why fog effects rarely get printed as raw toughness. A blanket +0/+4 at instant speed is built for one job: ambushing an alpha strike. The attacker commits, the blockers go up, and suddenly every trade the aggressor planned tilts the wrong way, with the defender's board surviving intact rather than chump-blocking. The +0 is the whole reason this is a fair card instead of a blowout: toughness buffs absorb damage but never turn the corner, so the defender gains nothing on the swing-back. That asymmetry is what separates a card like this from the more dangerous +X/+X tricks that punish a block and then close the game two turns later. Pump spells that add power want to be cast on offense; a power-of-zero spell only ever wants to be cast on defense, which narrows it to a reactive, go-wide insurance policy. The four toughness is generous enough to save creatures from most damage-based removal and nearly all combat damage in a board stall, but because the bonus does nothing for the defender's clock, the spell asks you to already be ahead on bodies and simply unwilling to lose them. It is combat math rendered as a single instant: a way to make a wide board's blocks lopsided in its favor for one turn, and nothing more.