Cloudstone Curio
The trigger reads like a value engine, but it is wired to loop. Because the returned permanent must share a type with the one entering, and because the return is optional, any pair of cheap creatures (or enchantments, or whatever shares a type) becomes a free bounce-and-replay cycle the moment a second source of value attaches to the play. Drop a one-drop, bounce another one-drop, replay it, bounce the first: every iteration that produces a benefit on entry (a mana trigger, a damage ping, a token, a life drain) chains until you choose to stop or run out of mana. That is the structural break from ordinary blink. Blink exiles and returns the same object on a clock you do not control; this hands you the object back as a card in hand and lets you decide when the loop terminates. The price is fragility. It needs two pieces minimum to recur anything, it does nothing on a board you cannot rebuild, and a single instant-speed answer aimed at one loop component can strand a creature in your hand mid-chain. So it sits dead until the rest of the engine arrives, then suddenly draws the line between a board state and a kill. What the design solves is how to grant repeatable enters-the-battlefield value to permanents that carry no recursion of their own, without stapling a dedicated bounce effect onto every card in the deck.








