Spellshock

A symmetric tax with no off switch, which is the whole design. Most damage-on-cast effects of this era hedged: they hit only the opponent, or only certain spell types, or asked you to pay something to trigger them. This one fires on every spell, from either side of the table, and never asks permission. That symmetry is the friction that makes the rate cheap: you cannot deploy it as a clean clock against an opponent without bleeding yourself, so the card belongs to a deck built to break the symmetry, either by playing fewer spells than the opponent or by holding a life total it does not mind spending. The effect reads more like a Manabarbs-style hate piece than a burn spell: it does not win games by dealing damage so much as it makes casting spells expensive, warping how both players sequence and how willing they are to empty their hands. It sits squarely in red's long tradition of enchantments that punish a game action rather than answer a threat, the same axis that Manabarbs, Citadel of Pain, and Price of Glory occupy, with the trigger keyed to the act of casting rather than to lands or mana. The trigger is unconditional and unstoppable short of removing the enchantment, which is exactly why it has never needed a restriction printed onto it.