Mizzix, Ingenious Spellcaster

Instant and sorcery spells you cast with X in their
mana cost cost {4} less to cast.
Whenever you cast and instant or sorcery spell
with X in its mana cost, draw a card and deal 2
damage to any target.
Mizzix tested spell after spell, each one nearly killing
her in the process, until she finally found the greatest
and most efficient way of casting spells.