Claim of Erebos, can i use this Enchantment on an opponent's creature and activate it's ability or since the "creature has..." only it's controler's (the opponent) can activate it? Thanks for the help.
Unfortunately for you, Claim of Erebos gives the ability to the creature. Since you don't control the creature itself, you don't have control over the ability your enchantment gave to that creature. In short, your opponent can happily activate the ability to hit you for two life and you can't touch it.
I can't think of an aura or equipment where you retain control of the relevant activated ability as an example. I'm sure someone can think of one if it exists. but there are cards with a passive ability, such as Canopy Cover which prevents the opponent from targeting his/her creature if you cast it on one of their creatures.
I can't think of an aura or equipment where you retain control of the relevant activated ability as an example. I'm sure someone can think of one if it exists. but there are cards with a passive ability, such as Canopy Cover which prevents the opponent from targeting his/her creature if you cast it on one of their creatures.