Equilibrium

The design idea is taxing the board not with a single tempo swing but with a recurring fee on a thing you were already going to do. Every creature you cast offers an optional to bounce, which fuses two decisions (developing your own board and disrupting theirs) into one trigger. The targeting is deliberately open ("target creature," not "target creature an opponent controls"), and that openness is where the flexibility lives. Pay the to send an opponent's expensive creature back to hand and you have bought a tempo tax that scales with how fast you flood the board. Aim it at your own enters-the-battlefield bodies (a draw-on-entry or kill-on-entry creature) and you have a repeatable engine that empties the opposing side while refilling yours, since the bounced creature comes back to be recast next turn. The cleverness is that the is cheap enough to fire on nearly every spell, so the meter just keeps ticking up. It is a soft lock rather than a hard one: the opponent keeps getting their creature back, so the card resets the battlefield rather than removing anything outright, and that softness is the balance. Bounce returns to hand, not to play, which means each loop costs a full recast: that friction keeps Equilibrium an engine piece rather than a finisher. The enchantment itself does nothing alone; it is the meter, and the creatures you loop are what make the math worth running.