Rienna, Nature's Maestro

Sacrifice Rienna, Nature's Maestro: Add one
mana of any color. If that mana is spent on a creature spell, that spell can't be countered, and that creature enters the battlefield with an additional +1/+1 counter on it.
Of all the musicians throughout the world, playing in castles, amphitheaters, and cities of all types, the most skilled is a self-taught elf living in a forest untouched by civilization.