Caltrops

Most deterrence effects from this era tax the opponent by making attacks cost mana or life. This one ignores the controller entirely and taxes the attack itself: every creature that swings, on either side of the table, simply takes a point of damage with no input from its owner. The design quietly inverts the usual assumption about how a punishment artifact works, shaving toughness off whatever crosses the line, and it does so symmetrically. That symmetry is the whole tension. A deck that doesn't attack pays nothing; a deck built on a swarm of small bodies pays a tithe it can't easily afford, since a board of one-toughness creatures evaporates the moment they're committed to combat. The card asks nothing of its owner beyond the discipline not to attack into its own teeth, which makes it a clean fit for the kind of grindy, defensive shell that wins without ever entering the red zone. The crucial limit is that it punishes only the act of attacking, not the creature's existence: a wide board sitting back loses nothing, and a single large attacker shrugs the ping off. The damage is a tax on aggression, not a removal spell, and reading it as the latter is the most common way players misjudge what it actually shuts down.