Stormscale Scion is a mythic Creature — Dragon card from Tarkir: Dragonstorm Promos (PTDM), collector number 123p. Current market price: $2.57 (foil $3.75), TCGplayer market prices via Scryfall.
Flying Other Dragons you control get +1/+1. Storm (When you cast this spell, copy it for each spell cast before it this turn. Copies become tokens.)