Devouring Demon

Enchant target creature with a Longsword
equipped.
Enchanted creature gains +3/-1, Vigilance and
"At the end of each combat phase if this creature
attacked or blocked put a +1/+1 counter on it,
if it didn't attack or block put a -1/-1 counter
on it."
If enchanted creature doesn't have a Longsword
equipped sacrifice Devouring Demon