When this enchantment enters, creature cards in your graveyard perpetually get +1/+1.
BlightTo “blight N” means to put N -1/-1 counters on a creature you control.
If a player is given the choice to blight but is unable to put N -1/-1 counters on a creature they control (usually because they control no creatures), they can’t choose to blight.
Some spells and abilities that instruct a player to blight refer to the “blighted creature.” This phrase refers to the object that the player who was instructed to blight chose to put -1/-1 counters on when blighting.
An ability that triggers whenever a player blights triggers after the process described in rule 701.68a is complete, regardless of what events actually occurred. (CR 701.68) X, Return this enchantment to its owner's hand: Return target creature card with mana value X or less from your graveyard to the battlefield. X can't be greater than the greatest toughness among creatures you control.
ActivateTo activate an activated ability is to put it onto the stack and pay its costs, so that it will eventually resolve and have its effect. Only an object’s controller (or its owner, if it doesn’t have a controller) can activate its activated ability unless the object specifically says otherwise. A player may activate an ability if they have priority. See rule 602, “Activating Activated Abilities.” (CR 701.2) only as a sorcery.