Fungal Creep

Vanishing 2 (This permanent comes into play with
two time counters on it. At the beginning of your
upkeep, if this permanent has a time counter on it,
remove a time counter from it. When the last time
counter is removed from this permanent, sacrifice it.)

Whenever a creature you controls deals combat
damage, flip a coin for each of those creatures.
For each flip you win, that creatures deals double
that damage instead.