Rule of 3s

This spell can't be countered.
Target opponents discards 3 cards, sacrifices 3 permanents, loses 3 life, mills 3 cards, and exiles
the top 3 cards of their library.
You draw 3 cards, gain 3 life, gain 3 mana in any combination of colors, seek 3 cards, put 3 cards
from your graveyard into your hand, exile 3
permanents, deal 3 damage to any 3 targets, and
put 3 +1/+1 counters on 3 creatures.
Flashback {3}{w}{w}{w}{r}{r}{r}{u}{u}{u}