In Two-Headed Giant, triggers only once per upkeep, not once for each player.
2005-08-01
When the enchanted creature leaves the battlefield, this card is placed into the graveyard as is normal for an Aura when it loses what it enchants. The triggered ability returns this card to the battlefield with no counters on it.
2004-10-04
A counter is placed on every player's upkeep, not just the controller's upkeep.
2004-10-04
The controller of the dead creature chooses the new creature.
Enchant creature
At the beginning of each upkeep, put a plague counter on this Aura.
Enchanted creature gets -1/-1 for each plague counter on this Aura.
When enchanted creature leaves the battlefield, that creature's controller returns this Aura from its owner's graveyard to the battlefield.
