Electric Revelation
Instant
As an additional cost to cast this spell, discard a card.
Draw two cards.
Flashback 
(You may cast this card from your graveyard for its flashback cost and any additional costs. Then exile it.)
Liiga Smilshkalne
Rulings
If you cast Electric Revelation using flashback, you must still pay its additional cost of discarding a card.
(wotc • 2021-09-24)
Rulings
If you cast Electric Revelation using flashback, you must still pay its additional cost of discarding a card.
(wotc • 2021-09-24)