Mana Geyser by paying ({3} magic symbol) ({R} magic symbol) ({R} magic symbol) , adding ({R} magic symbol) for each tapped land your opponents control.
Cast
Devastating Onslaught by paying ({4} magic symbol) ({R} magic symbol) , creating two token copies of
Salvager of Secrets with haste.
When the
Salvager of Secrets tokens enter, they trigger, returning
Mana Geyser and
Devastating Onslaught from your graveyard to your hand.