Acrobatic Cheerleader

Attack, stay tapped, and hope the body lives long enough for the reward to land: a 2/2 that swings and stays tapped through the postcombat check earns a permanent flying counter, after which the mechanic falls silent. The trigger's phrasing is where the real design sits. It reads only the creature's tap-state, so any tap qualifies, not just an attack; a body tapped for a mana ability or an activation satisfies the same condition as one that went to combat. What defeats the reward is untapping, which is why vigilance runs against this design rather than with it: a vigilant attacker never taps to swing, so the postcombat check finds nothing to upgrade. The "only once" clause caps the payoff at a single evasion upgrade, earned and then finished, keeping a common from snowballing. The tension is that the counter only arrives if the creature survives the swing that tapped it, so the intended line is to send the 2/2 into combat and hope it comes back. It asks players to track board state in a window where most hands are already reaching for the next land drop, a quiet demand to build a common around. The body trades into most early creatures on its own; the flying counter is the reason to risk it anyway.