Mollymauk Tealeaf

Each creature spell you cast with mana value
4 or greater has blitz. The blitz cost is equal
to it's mana cost. (You may choose to cast that
spell for it's blitz cost. If you do, it gains haste and
"When this creatures dies, draw a card." Sacrifice it at the beginning of the next end step.)

Blitz costs you pay cost {1} less for each
time you've cast your commander from the command zone this game.