Flock Impostor

Flash and flying on a Shapeshifter is the giveaway: this is a bounce-blink piece dressed as a combat trick. The enters trigger returns another creature you control to hand, which reads like a downside until you notice how much white weenie and value-creature design leans on entry effects. Flashing it in at the end of an opponent's turn to reset a tapped attacker, save a creature from a removal spell already on the stack, or reload a one-shot enters-the-battlefield trigger turns a plain 2/2 body into a repeatable engine's release valve. Changeling is the quiet multiplier: because it registers as any tribe you name, the body doubles as a lord target and an anthem beneficiary while it waits to blink something better. The "up to one" wording matters as much as anything, because it lets the card come down as a straight flash flyer when there's nothing worth returning, so the ability never strands you the way a mandatory bounce would. It sits in a long line of self-bounce enablers, but most of those wanted their bounce stapled to something cheaper or slower; putting the effect on a flash-flying body folds the tempo cost into a creature that already earns its slot.