Enchant creature you control
When Cartouche of Ambition enters the battlefield, you may put a -1/-1 counter on target creature.
Enchanted creature gets +1/+1 and has lifelink.
4/18/2017 The target creature for the triggered ability of Cartouche of Ambition doesn’t have to be the creature it enchants.
4/18/2017 Cartouche is an enchantment subtype with no special meaning. Other cards may care about which enchantments are Cartouches.
4/18/2017 If the target creature becomes an illegal target before a Cartouche spell resolves, the spell doesn’t resolve. It doesn’t enter the battlefield.
4/18/2017 Each Cartouche is an Aura with “Enchant creature you control.” If another player gains control of either the Cartouche or the enchanted creature (but not both), then the Cartouche will be enchanting an illegal permanent and be put into its owner’s graveyard as a state-based action.