Eira, Ice Dragon's Protégé

Dragon creature spells cost {1} less to cast.
Whenever you cast a Dragon spell, you may pay {r}{r}. If you do, target player takes damage equal to
Eira's power.
Whenever you cast a Dragon spell, you may pay {u}{u}. If you do, Eira gains flying and +1/+1 until
end of turn.
Eira's toughness is equal to the number of Dragons
you control.