You may cast spells from exile with memory counters on them.

Spells you cast from exile have Replicate— {1}{G}{U}.

Spells you cast from exile can't be countered.

Whenever you cast a spell from anywhere other than exile, you may exile it with a memory counter on it. If you do, at the beginning of your next precombat mainphase, add X mana in any combination of colors where X is the mana value of the exiled card. Do this only once each turn.