Goblin Sharpshooter | Splinter Twin

Cards

Goblin Sharpshooter and
Splinter Twin on the battlefield.
Splinter Twin attached to
Goblin Sharpshooter.
Goblin Sharpshooter does not have summoning sickness.
You have a way to cause a non-
Goblin Sharpshooter creature to die (for an additional result).

Activate
Goblin Sharpshooter's ability from
Splinter Twin by tapping it, creating a token copy of
Goblin Sharpshooter with haste.
Activate the token copy of
Goblin Sharpshooter by tapping it, dealing 1 damage to itself.
The token copy of
Goblin Sharpshooter dies, triggering the nontoken
Goblin Sharpshooter, untapping it.
Repeat.
Alternatively, if you have a way to cause any creature besides the
Goblin Sharpshooters to die, for instance by targeting a 1-toughness creature in step 2, you can untap
Goblin Sharpshooter an additional time and repeat step 1 one additional time before continuing the combo.
This will leave you with one additional surviving
Goblin Sharpshooter token, which can activate itself once per loop for infinite damage to any targets.