I'm not sure exactly what you're talking about either.
Do you mean like a Bash that isn't Passive but activated and lasts for X time?
If so, just make a Dummy ability based off bloodlust, remove all buffs (Attack speed increase etc) from it. Then make the custom bash spell, change it to however you want (100% chance to stun, X ammount of damage per rank or whatever). Then create a trigger to give the Real ability to the hero and wait X ammount of time and then remove it.
If you just want a targetted stun + dmg, then do as the above poster said, make an ability off of stormbolt, reduce the range and the projectile model.