Spark Double | Murderous Redcap | Ashnod's Altar

Cards

All permanents on the battlefield (
Spark Double as a copy of
Murderous Redcap).

Activate
Ashnod's Altar by sacrificing
Spark Double, adding ({C} magic symbol) ({C} magic symbol) .
When
Spark Double dies, its persist ability triggers, returning it from your graveyard to the battlefield with a -1/-1 counter on it.
As
Spark Double enters the battlefield, choose to have it enter the battlefield as a copy of
Murderous Redcap with a +1/+1 counter on it.
When
Spark Double enters the battlefield, it triggers, dealing damage equal to its power to any target.
Repeat.