Keyword: Flashback

Lava Dart deals 1 damage to any target.
Flashback—Sacrifice a Mountain. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Create three 6/6 green Wurm creature tokens.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Destroy target enchantment.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Damage can’t be prevented this turn.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Prevent all damage that sources of the color of your choice would deal this turn.
Flashback—Tap an untapped white creature you control. (You may cast this card from your graveyard for its flashback cost. Then exile it.)

Lightning Surge deals 4 damage to any target.
Threshold — If seven or more cards are in your graveyard, instead Lightning Surge deals 6 damage to that permanent or player and the damage can’t be prevented.
Flashback (You may cast this card from your graveyard for its flashback cost. Then exile it.)