Offspring's Revenge and Pandemonium on the battlefield.
Steps
At the beginning of your combat phase, Offspring's Revenge triggers, exiling Tree of Perdition from your graveyard and creating a 1/1 copy of it with haste.
The Tree of Perdition copy enters the battlefield, triggering Pandemonium.
Holding priority, activate the Tree of Perdition copy by tapping it, exchanging its toughness with target opponent's life total.
Resolve the Pandemonium trigger, causing the Tree of Perdition token to deal one damage the opponent whose life total was swapped.
The opponent loses the game due to having zero or les life.