Acacius, Master Negotiator

Instant and sorcery spells you cast have: Your
opponents may spend mana as though it were
mana of any color to help cast this spell
Whenever an opponent helps cast a spell you
control they may draw a card
Whenever you cast an instant or sorcery spell,
you may copy it for each player other than you
who spent mana for this spell. You may choose
new targets for the copies