Since the producer update there is a way to change Ability tooltips with variables, however this affects any unit using the ability.
It's under UNIT - change tooltip extended to <entered string>
Default Sleep on it's own is hard coded to be single target, you want aoe sleep you'll need to trigger it, base the ability off of Channel and make the initial level single target and the higher levels point target.
if this is too difficult I can make it easy peasy.
Create a trigger that detects the spell cast. ( lets say berserk, I like it because it doesn't interrupt unit's orders.)
Increase the unit's maximum mana by 500 (be sure to restore mana equal to the mana max added as it doesn't do this automatically)
Add the unit into a unit group
Create a...
Waits will make your map hemorrhage leaks, best to pretend they don't exist in your maps ever...
Be back with further analysis
EDIT:
Start looking into Unit Indexing & Damage Engine By Bribe
These are the systems I'm going to use to try and redo your spell
Damage engine can be used to trigger...
Boom made with a Damage Engine
Added a detail to the spell (you can remove it by getting rid of the condition and the dummy casting the debuff) That fizzles the unit making temporarily disabled.
EDIT
Didn't know this thread was 3 god damn years old...
Damage Engine will solve your problems
The map file contains Bribe's system along with the custom ability provided
The spell is on the Fallen priest and a few minions with very low health to test on
EDIT
Didn't know this thread was 2 god damn years old...
Try *Bribes Damage engine
No jass and easy to use!
The map I provided is the system along with the Mana shield trigger i've edited to damage an attacking unit dealing (5 x lvl of mShield) + 15% + 5% per level of the damage dealt by the attacking unit!
The mana shield is currently on Naga...
Basically I was trying to look into a triggered damage Dot (based on the casters intelligence) that spreads to another unit if the effected unit dies.
If you play league of legends, there is a hero name Malazhar, and he has the exact ability. Heres a description of the spell:
I tried...
Basically your pause unit trigger should be out of the initial cast simply because it paused the caster while he was still casting, resulting it to recast it indefinitely.
enjoy!
"Oh boy can't wait to use my poison projectile! OH DEAR!"
"What's the matter Billy?"
"Holy macaroni mister, my shadow strike has FLOATING TEXT!"
"Say Billy do you want a poison projectile with no FLOATING TEXT?"
"Why sure mister, but all I have is this here handy dandy shadow...