Not sure if this is possible, obviously it's not possible at the same time but I've run into a couple of spells which apply a debuff and when the target dies then give the player a buff.
Currently it's not possible to track this.
Nemesis http://bfa.wowhead.com/spell=206491/nemesis

Soul Reaper is the other. http://bfa.wowhead.com/spell=130736/soul-reaper