You have an amount of ({R} magic symbol) available equal to three minus the number of +1/+1 counters on
Runaway Steam-Kin.
Notable Prerequisites
You control at least one Mountain.
.
Steps
If
Runaway Steam-Kin has three or more +1/+1 counters on it, activate it by removing three +1/+1 counters from it, adding ({R} magic symbol) ({R} magic symbol) ({R} magic symbol) .
Cast
Spear Spewer by paying ({R} magic symbol) .
Runaway Steam-Kin triggers, putting a +1/+1 counter on it.
Activate
Spear Spewer by tapping it, dealing 1 damage to each player.
Dissipation Field triggers, returning
Spear Spewer from the battlefield to your hand.
Repeat.
Notes
It is recommended to perform this combo when you have more life than your opponents to end the game, but it is not required. If this combo will not end the game, stop once you have 1 life.