Nekusar, the Mindrazer | Echo of Eons | Triumph of the Hordes

Cards

Echo of Eons in hand.
Nekusar and
Triumph of the Hordes on the battlefield.
({6} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) ({U} magic symbol) if each opponent has three or more poison counters, or ({8} magic symbol) ({G} magic symbol) ({G} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) otherwise available.

Cast
Triumph of the Hordes by paying ({2} magic symbol) ({G} magic symbol) ({G} magic symbol) , giving creatures you control +1/+1 and infect until end of turn.
Cast
Echo of Eons by paying ({4} magic symbol) ({U} magic symbol) ({U} magic symbol) , causing each player to discard their hands and draw seven cards.
Nekusar triggers for each card your opponents draw.
Resolve the first trigger, causing the opponent to get a poison counter.
If the opponent has ten or more poison counters, they lose the game as a state-based action.
Repeat from step 4 for each remaining trigger.
If needed, cast
Echo of Eons from your graveyard for its flashback cost by paying ({2} magic symbol) ({U} magic symbol) , causing each player to discard their hands and draw seven cards.
Repeat from step 3.