Venomancer

{g}, {t}: Create a 1/1 green Plague Ward creature token with, "{t}: Deal 1 damage to
any target."
{5}{g}: Put a -1/-1 counter on each creature your opponent's control. Creatures with -1/-1 counters on them have, "at the beginning of each upkeep, put a -1/-1 counter on this creature, only if its toughness is greater than one."
"A touch of venom."