Conduit Mage

Bestow {2}{w}{u}{r} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Enchant creature gets +2/+2.
Conduit Mage and enchant creature have, "Whenever you cast an instant spell during your main phase, you may discard a card, if you do, draw a card."