Mist Raven

Tempo, packaged as a creature. The bounce-on-entry effect was old long before this design: Man-o'-War set the template at three mana for a 2/2 with no evasion, returning a creature when it hit the battlefield. The wrinkle here is the upgrade to flying and the extra mana that pays for it. Where Man-o'-War clutters the ground and gets chumped, this one returns a blocker, then keeps attacking through the air, so the same enters-the-battlefield trigger that buys a turn of tempo also leaves behind a body that closes the gap it just opened. That double-duty is the whole appeal: blink it, flicker it, recur it, and each loop strips a creature off the board while a 2/2 flyer chips away. The trade-off is the four-mana price tag and a fragile 2/2 that dies to nearly any removal once the trigger has resolved, which keeps the effect from being a free two-for-one. Bounce is also temporary by nature: the target comes back, the enters-the-battlefield triggers reset, and against a card the opponent wants recast, you have only delayed it. Against a creature that cost real resources to deploy (a reanimation target, an enchanted attacker, a freshly cast bomb), the tempo swing is brutal, and the flying body makes sure the turn you bought does not go to waste.