Serendib Sorcerer

A blue rendering of an effect that once lived elsewhere: a tapper that does not tap, instead crushing a creature's base power and toughness to 0/2 for the turn rather than incapacitating its body. That distinction governs everything the card does. A blocker reduced to 0/2 still blocks; it just deals no damage, so it absorbs an attacker without killing it, and any creature with two power can kill it cleanly on offense. The repeatable activation lets it shrink a different attacker each turn, or turn an opponent's beater into easy prey for one of your own, all without spending a card. Paying for that flexibility is the body and the cost: a 1/1 that taps to do its work is fragile, telegraphed, and slow, easy to kill before it generates a second activation. The base-power-and-toughness clause is also more selective than a flat debuff suggests, since setting base P/T happens before pumps and counters apply in the layer system: a buffed attacker keeps its +X/+X on top of the new 0/2 floor, so this answers vanilla beaters far better than something already wearing an aura or a stack of counters. It rewards a patient, control-leaning shell willing to protect a fragile wizard long enough to grind, the kind of incremental, attrition-minded blue this era of design kept circling back to.