Thassa's Ire

A one-mana enchantment whose only function is a four-mana tap-or-untap, fireable as many times as your mana holds out. The tension is between the trivial deploy cost and the expensive activation: it enters doing nothing and exists to bank a repeatable effect for later. The tap line is removal-adjacent in the soft sense (the Frost Titan school of stranding a blocker or an attacker for a turn), while the untap line is the engine half, vigilance-on-demand for a creature with a worthwhile tap ability or a mana dork you want to milk twice. Neither mode is efficient at four mana a pop; the design assumes a late game where mana is abundant and a one-mana permanent has long since paid for its slot. Permanence is the actual point. An instant that did this once would go to the graveyard; here the ability stays put, a standing threat of activation that quietly converts surplus mana into board control over a long game. It is the inverse of a tempo card: no early impact, no flash, just a cheap enchantment you leave in play and forget until the turn it starts to matter.