Mr. Orfeo, the Boulder

Power-doubling on attack sounds explosive until you notice how narrow the trigger really is: it fires during your own declare-attackers step, before blocks are chosen, and it hits exactly one creature. The obvious line is a 2/4 that turns a 4/4 into an 8/4 or shoves a trampler into lethal, but the ability does nothing on a turn you hold back. The wording is "double target creature's power," not "double an attacker's power," which is the wrinkle that widens the card past raw combat math: the target does not need to be attacking at all. Because the trigger fires the moment you swing, you can double a creature that sat back specifically to feed a fight spell, a damage-based draw effect, or trample calculations elsewhere on the board, then let the number revert at end of turn. It multiplies rather than adds, so it stacks cleanly with +1/+1 counters (the doubled figure counts the counters, then falls off) and with anything that reads power directly. What keeps it honest is the combat-locked window: no instant-speed flexibility, no second doubling off a single attack, one target per swing, and a body soft enough that it wants a board already leaning forward rather than one it assembles from nothing. The extra power is only worth what you have on hand to cash it into.