Cloudpiercer

Mutate asked designers a specific question: what does it look like to pile abilities onto a creature without piling on card slots or resetting summoning sickness each time you commit resources? This one answers with card selection. Every time the stack of creatures mutates (the first cast, and every mutation after), you may rummage: discard a card, then draw one. That quietly resolves mutate's central tension, since the deck wants to draw its mutating payloads but also needs land and setup, and pitching an excess into a fresh card on each mutate trigger smooths the curve without demanding a dedicated draw engine. Discarding before drawing matters, too: it lets the pile feed a graveyard while it filters, so the loot direction is not merely cosmetic. The reach is the other half of the pitch, and it earns its slot rather than sitting as flavor filler. A mutate pile is a single fat threat, which makes it exactly the kind of investment that dies to a flier while its controller has nothing to block with; grafting evasion-defense onto the stack keeps that threat alive against the air. Read as a standalone body it is unremarkable; read as a component in a mutate chain it is the piece that keeps the hand flowing, so the pile does not run out of gas before it runs over the opponent. That is the whole design brief for a mutate enabler: give the archetype a reason to keep triggering, and reward it with selection each time it does.