Nekusar, the Mindrazer | Echo of Eons | Phyresis

Cards

Echo of Eons in hand.
Nekusar and
Phyresis on the battlefield.
Phyresis attached to
Nekusar.
({4} magic symbol) ({U} magic symbol) ({U} magic symbol) if each opponent has three or more poison counters, or ({6} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) otherwise available.

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 3 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 2.