Something like Mark of Thor, giving the target +2 lightning, and whenever a creature in the same or an adjacent zone is damaged by a lightning attack the controller (of the curse) may pay 1 mana to split the dice of the attack between the other target and the lighning curse creature.
In effect youd pay extra and diverting some power from the main target, but since the curse also gives lightning +2 even redirecting a single dice to the cursed creature makes for a nice 2 dice attack.
(and you could do a really nasty combo if you manage to hit lots of creatures next to a curse target with electrify.)
