Primal Amulet [Ixalan]

Instant and sorcery spells you cast cost {1} less to cast. Whenever you cast an instant or sorcery spell, put a charge counter on Primal Amulet. Then if there are four or more charge counters on it, you may remove those counters and transform it.

(Transforms from Primal Amulet.) {T}: Add one mana of any color. When that mana is spent to cast an instant or sorcery spell, copy that spell and you may choose new targets for the copy.