Coinhive

Enchant creature
Logic Bomb {r}{r} (You may cast this face down for {3} as an Aura spell with enchant creature. Turn it
face up any time for its logic bomb cost.)
When Coinhive is turned face up, add {r} for each creature enchanted creature's controller controls.
{r}: Coinhive deals 1 damage to enchanted
creature. Activate this ability only any time you
could cast a sorcery.