Chaly, The Wings of War

This spell costs {b/g} less to cast for each instant
and sorcery spell you’ve cast this turn.
Whenever Chaly attacks, exile up to one target
instant or sorcery card from your graveyard.
Copy it. You may cast the copy.
You may cast Chaly from your graveyard by
exiling four instant and/or sorcery cards from
your graveyard in addition to paying its
other costs.