How many times have you wished to be able to give a thousand gold to get to that one jerk that just really pisses you off and melt his disgusting face off? How many times have you been killed by someone that you KNOW for a fact you could have beaten if it wasn’t for fucking outside interference (even if you would only have had 5 hp left at the end of the fight).
How many times has a person started a fight with you only to stand back like a coward and let others finish you off? How many times have you died when some retarded warrior/DK/rogue beats off in your face while some mentally handicapped hunter spams one button at you from 50 yards away that ends up killing you? How many times have you just wished to be able to go one on one with that ONE person on the other side who you respect enough to consider your equal and would relish a personal 1v1 test of skill with?
Curse of Hatred
5 min cooldown
Instant cast
Only the cursed target may deal damage to you. You and the cursed target are immune to damage from all other sources and you may only deal damage to each other. The cursed target and you may also not receive help from an ally or outside source (no outside heals, buffs, despells, etc….) for the duration of the curse. Lasts for 20 seconds.
-You may only target the cursed target and deal damage to him; all damage
  you would deal to other targets is reduced to 0.
- The cursed target may only deal damage to you; all damage he would deal
   to others is reduced to 0.
- You cannot receive help from an ally/outside source. (No heals, despells,
   bubbles, buffs, bandages from others, etc …)
- The cursed target cannot receive help from an ally/outside source. (No heals,
   despells, bubbles, buffs, bandages from others, etc …)
- Obviously a hunters pet and your pet would come along with you into the other
   out of phase world.
Basically it’s a one on one fight. You take someone who just really pisses you off out of the rest of the world around both of you and go one on one with him. No bullshit help, no bullshit outside interference, no bullshit “target is out of range” while some disgusting warrior/Dk beats off in your face. One versus one – either destroy your opponent and make him wish he had never pissed you off or die with dignity since you weren’t good enough to beat him.
Would employ blizzards new phasing technology, were both of you would be in the same place just “out of phase” and won’t be able to see or be seen by anybody else. Or it doesn’t even have to. You and your cursed target could just glow purple or something and can’t damage anyone else except each other for the duration. At the end after the 20 seconds are up both of you are returned to the normal world, unless one of you dies in which case that person stays dead and the other returns.
Obvious other measure/balancing would be taken to prevent it from being used as an exploit or whatever (can't cast on bosses, can't cast on allies, duration reduced/extended, cooldown changed etc ....)