Conundrum Sphinx

A flying body that turns its own attack step into a guessing game both players have to play, and the symmetry is the whole gambit. The trigger doesn't favor the attacker by default: whenever it attacks, you and your opponent each name a card, each flip your top card, and each keep it on a hit. On paper that's even, which is why the design lives entirely in the asymmetry of information. You know your own deck's ratios, your draw spells, your fetch and shuffle effects; your opponent is guessing into the dark. A player who has tutored, scryed, or otherwise stacked the top of their library walks into the trigger already knowing the answer, while the defender is stuck calling card names blind. The trigger fires on declaration, not on damage, so it pays out the moment you swing rather than asking the Sphinx to survive blockers first; every clean attack feeds the same low-variance stream of cards, but only for the player who has done the deckbuilding to make their own guess a formality. The 4/4 evading frame does the actual work of ending the game while the attack trigger quietly compounds the card-advantage gap each time it swings. The honesty of the symmetry is a feint: this is an advantage engine dressed up as a fair coin flip, and it punishes nobody more than the opponent who has no idea what's coming.