Myra, Spellsplitter Adept

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever an instant card is put into your
graveyard, if you cast it, target opponent may
have Myra deal 3 damage to them. Otherwise
that card gains Jump-start until end of turn.
(You may cast that card from your graveyard by discarding a card in addition to paying its other
costs. Then exile that card.)