Kenrith's Transformation
For most of the game's history, permanent-based answers that neutralize a threat rather than kill it belonged to white and blue: pacifism effects, control-magic effects, the toolbox of "it's still there, but it can't hurt you." This does that same work in green's idiom, and the mechanic is the tell. It does not destroy or exile; it overwrites. Everything that made the enchanted creature dangerous (its abilities, its stats, its very card types) is replaced with a vanilla 3/3 Elk body, a downgrade often steep enough to end a game plan even though the creature stays on the battlefield. That "still there" clause is the honest cost: you have not answered the permanent so much as defanged it, and it can still block, still be sacrificed, still ride out a board wipe as a body. Stapling a card to the front of the aura is the insurance against ever drawing it dead: even against a board with nothing worth transforming, it replaces itself and shrinks something incidentally. The design lineage runs through Beast Within and Song of the Dryads, green's tradition of hitting anything at the price of leaving a trace, but this one narrows the target to creatures and pays you back with a card instead of gifting the opponent a token. That trade (narrower scope, cleaner rate, cantrip attached) is why it reads so unremarkable and plays so much better than it reads.
