Dollhouse of Horrors and Pandemonium on the battlefield.
({1} magic symbol) available.
Steps
Activate Dollhouse of Horrors by paying ({1} magic symbol) , tapping it and exiling Tree of Perdition from your graveyard, creating a token copy of Tree of Perdition that is a 0/0 Construct 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 damage equal to its power to each opponent.
The opponent whose life total was swapped loses the game due to having zero or les life.