"Fifth Edition", +m/(loses?|restart|win)\sthe\sgame/ (3)
Whenever Marsh Viper deals damage to a player, that player gets two poison counters. (A player with ten or more poison counters loses the game.)
Whenever Pit Scorpion deals damage to a player, that player gets a poison counter. <I>(A player with ten or more poison counters loses the game.)</I>
, : Create a 1/1 colorless Snake artifact creature token. It has "Whenever this creature deals damage to a player, that player gets a poison counter." (A player with ten or more poison counters loses the game.)
Gatherer works better in the Companion app!
, 
: Create a 1/1 colorless Snake artifact creature token. It has "Whenever this creature deals damage to a player, that player gets a poison counter." (A player with ten or more poison counters loses the game.)