Fluttershy is a mythic Legendary Creature — Pegasus card from Secret Lair Drop (SLD), collector number 1538. Current market price: $36.62 (foil $37.92), TCGplayer market prices via Scryfall.
Defender, flying {1}, {T}: Put a +1/+1 counter on each creature with a tail target player controls. Stare down up to one target creature until end of turn. (It can't attack or block as long as you're looking directly at it.)