Befuddle

Power reduction is the quietest combat answer blue gets, and the reason this instant reads as filler until the one turn it saves your life. It does not kill the creature, does not tap it, does not bounce it: it shaves four power off a single body until end of turn and refunds itself with a card. Against an attacker that has already declared, dropping its power to zero or near-zero turns a lethal alpha strike into a non-event while the creature itself sits there untouched, and the cantrip means you have not lost a card doing it. The catch is the duration: the effect ends with the turn, so the creature is back at full strength next combat. This is a Fog aimed at one attacker, not a removal spell. Blue has shipped this template repeatedly (a -X/-0 instant stapled to card replacement) because the color is licensed to neutralize damage and dig for answers, not to permanently erase a threat. Befuddle sits squarely in that tradition, priced so the card draw is part of the deal rather than a bonus tacked onto a defensive spell. The reduction and the draw are not a choice between modes; you get both every time, which is exactly what keeps a card this narrow worth a slot in a tempo deck that would otherwise cut it.