Poison Team

Whenever Poison Team deals combat damage to a creature, put an infection counter on it. As long as that creature has an infection counter on it, it has "At the beginning of your upkeep, flip a coin for each infection counter on this creature. If any of them come up heads, put a -1/-1 counter on this creature."
Whenever Poison Team deals combat damage to a player, that player gets an emblem with "At the beginning of your upkeep, flip a coin. If it comes up heads, you lose a life."