Xeru's Apprentice, Tylii

{p/u}{p/b}, Sacrifice a creature: Place 1 Venom
counter on target player. (At the beginning of
each upkeep, players discard cards equal to the
amount of Venom counters on them.)
When Xeru's Apprentice, Tylii, deals combat
damage to a player with Venom counters on
them, draw X, where X is equal to the amount
of Venom counters on that player.