Anomaly Chaser

This spell costs {u} less to cast if you control
an artifact, {b} less to cast if you lost life this
turn, {r} less to cast if an opponent lost life
this turn, and {g} less to cast if you control
a Beast or a Mutant.
When Anomaly Chaser enters, if it was cast
and no mana was spent to play it, you may
shuffle it into your library. If you do, mill
thirteen cards, then draw two cards.