Kiri-Onna

The bounce-on-entry creature was a known quantity long before this Spirit arrived, but the second ability rewrites how often that entry happens. Most enters-the-battlefield value is a one-time fee: you pay the mana, you get the trigger, the creature stays put as a vanilla body. Here the body is built to leave. Cast another Spirit or Arcane spell and you may send this back to hand, which means you re-buy the bounce next turn, and the turn after that, for as long as the deck keeps feeding it spells. The 2/2 frame is almost beside the point; the card is a reusable Unsummon engine wearing a creature's clothes, and the only cost of recurring it is the tempo of recasting at five mana each loop. That price is what keeps it honest, since a free or cheap recursion loop on a repeatable bounce would simply lock an opponent's best creature out of play. The self-return clause is also a clean fit for a deck already chaining cheap Arcane spells and splice effects: the same casts that fuel your tempo plan trigger the eject button, so the bounce is not an extra thing you build around but a dividend of doing what the deck already wants. What the design captures is the era's notion that a creature's ability could be a recurring resource rather than a stat line, with the body as little more than a delivery mechanism for the trigger.