Donal, Herald of Wings
The narrowness is the point. Most copy-matters designs cast a wide net: any creature, any spell, sometimes any permanent. This one carves out a single lane, nonlegendary creature spells with flying, and pays it off with a duplicate that does not inherit the original's stats at all. That is the design's cleverest constraint: the copy arrives as a 1/1 Spirit stapled onto whatever it was already, so you are not doubling a payoff body, you are minting a small evasive token that happens to carry every other type and ability the original spell had. The subtype rider is the quiet hook. Because the copy is also a Spirit, an evasive flying shell suddenly gains a token generator that feeds Spirit lord effects and go-wide payoffs without any of those Spirits appearing on the cast side. The once-per-turn clamp keeps the engine from spiraling, so this rewards casting one high-value flyer per turn rather than chaining cheap ones: the spells it wants are ones whose enters-the-battlefield value or triggered abilities survive the shrink to a 1/1. There is friction in the color, too. Mono-blue does not natively field a deep bench of splashy flyers, so the build leans on the breadth of blue's evasive rosters rather than on raw beaters. What it represents is an answer to a specific design question: how do you make a copy effect a puzzle instead of a value faucet? Name the exact spell, and hand back a token that changes tribe on the way out.
