Cast Peer into the Abyss by paying ({4} magic symbol) ({B} magic symbol) ({B} magic symbol) ({B} magic symbol) , causing an opponent to draw cards equal to half their library and causing them to lose half their life total, rounded up.
Nekusar triggers for each card drawn this way.
Resolve the first trigger, dealing 1 damage to the opponent.
If the opponent has 0 or less life, the opponent loses the game due to having zero or less life.
Repeat from step 3 for each remaining trigger and/or until the opponent loses the game.