Spells can't be countered.

Each instant and sorcery card in your graveyard has flashback. The flashback cost is equal to that card's mana cost.

If it's neither day nor night, it becomes day as Vadrik, Astral Archmage enters the battlefield.

Instant and sorcery spells you cast cost less to cast, where X is Vadrik's power.

Whenever day becomes night or night becomes day, put a +1/+1 counter on Vadrik.