Fungus

Parasite {2}{b}(as an alternative to casting
you may pay {2}{b} and exile this creature
from your can and put a parasite counter
on target creature; at the beginning of each
upkeep put another parasite counter on each
creature that has one. When the the number
of parasite counters exceeds its toughness
sacrifice that creature and return this creature
from exile to the battlefield with a number of
copies equal to the toughness of the "host")
{1}sac this: draw a card