Mercurial Transformation

The load-bearing text is the same one Turn to Frog leaned on: the target loses all abilities, so protection, evasion, or a creature that doubles as an activated engine goes dark until end of turn. What separates this design from that older polymorph-into-a-vanilla-body line is that the caster picks the resulting body after the abilities are stripped, choosing a shrink or a swell rather than being locked into one fixed answer. The 1/1 Frog is the neutralizer: cast it in your main phase before combat, then attack past a blocker that can no longer trade up or activate anything. The effect resolves and expires within your own turn, and because this is a sorcery it never reaches across to the opponent's attack step; the transformation is a proactive tempo play, not a removal spell and not a defensive trick. The 4/4 Octopus inverts the target entirely, aimed at one of your own untapped creatures to make a modest body swing far above its printed stats for a turn: note that the spell only reassigns power and toughness, it does not untap, so a creature already tapped for its own ability stays tapped and cannot join the attack. Both modes trade on the same erasure of text; the only question is which shape you want that erasure to wear. Restricting it to sorcery speed is what pins the whole package to your own turn, where it functions as setup for an attack rather than as a reactive answer to one.