Innocent Bystander

Most Investigate triggers are volitional: you attack, something dies, an enter-the-battlefield ability resolves, and the Clue appears on your terms. This one waits for violence, and specifically for overkill. The trigger cares about damage dealt in a single instance, not damage accumulated, and it wants three or more, which is the design's real wrinkle: a one-toughness body dies to almost anything, but it dies to a Shock or a routine 2/2 block without investigating. The payoff is reserved for the oversized hit: the burn spell that overpays, the removal that was pointed at something bigger, the four-power attacker it chumps in the red zone. That gap between "enough to kill it" and "enough to pay off" is where the flavor and the math meet: the bystander catches a stray shot, and only a genuinely reckless one leaves evidence behind. It reframes the exchange less as protection math and more as a small tax on how an opponent chooses to spend their damage, since anything that clears it cheaply denies the Clue while anything heavy-handed hands you a card. The 2/1 does its aggressive job on the way in either way; the investigate is a rider that rewards you specifically when the opponent swats it with more force than it was worth, and punishes nothing when they do the efficient thing instead.