Fractalize

The trick is that it does not care what a creature already is: it overwrites the identity down to the base. Point it at an opposing threat and you have blue interaction that shuts off tribal synergies (the creature loses all its types) and, when you set X low, cuts a large attacker down to a body barely worth blocking. Point it at your own board and it is a mana-scaling pump at instant speed on any creature you please. Folding the shrink and the grow into one variable-cost instant is the design idea; most stat-editing effects live on one side of the table, and giving a single card the range to work both is what makes it flexible. Just be precise about what it touches. This sets base power and toughness, which sits below counters and other bonuses in the layers, so a threat carrying +1/+1 counters or a static anthem keeps those modifiers stacked on top of the new base. It also leaves abilities untouched: unlike Turn to Frog, which zeroes out keywords along with the stats, Fractalize only rewrites colors, creature types, and base numbers, so a first striker with a Sword still swings with first strike and the equipment bonus. Reading it as a full off-switch is the mistake; it is a stat rewrite and a type wipe, no more, and the value is in how cheaply it reaches both ends of that range.