Heartless Hidetsugu and Goblin Goliath on the battlefield.
None of the involved permanents have summoning sickness.
Opponents have even life totals.
({3} magic symbol) ({R} magic symbol) available.
Steps
Activate Goblin Goliath by paying ({3} magic symbol) ({R} magic symbol) and tapping it, causing you to deal double the damage to opponent this turn.
Activate Heartless Hidetsugu by tapping it, causing it to deal damage to each opponent equal to the opponent's life total, and to you equal to half your life total, rounded down.
Each opponent loses the game due to having zero or less life.