Cobra Trap

Four 1/1 Snakes is not a six-mana payoff anyone intends to pay for, and that sticker price exists mostly to keep the card from being free. The whole design lives in the alternative cost: pay instead, but only after an opponent has destroyed one of your noncreature permanents with a spell or ability this turn. The fantasy is a vengeful counterpunch at instant speed, your artifact, enchantment, or land gets blown up and you flood the board in response, turning their removal into your tempo for a single mana on their turn. As retaliation design it is clean, and unlike a held removal spell the opponent gets no read on it: this is the kind of Trap that turns an opponent's correct play (kill the dangerous permanent) into a liability they could not have priced in. The tension is structural, not psychological. The discount requires the exact sequence the card punishes, so its window is entirely contingent on what an opponent decides to do for reasons of their own, and a destruction effect that hits the right permanent at the right moment simply may not arrive. When the trigger lines up the value is real; most games it idles in hand waiting for a condition it cannot manufacture. Revenge priced beautifully, gated behind a door only the opponent can open, and one they have no reason to suspect leads anywhere.