question on a new spell..?

[The Twin Tailed Comet]

i wanna make a new spell called "undead aura"
so wat the aura do is give all the undead unit (ur unit, enemy unit or friend's unit) in a number of radius, +xx% life regenerate, and 50% evation...
also u can only get this aura from an item called Lillith's Soul Stone(which i'm gonna make one)

i need help on how 2 make this spell
help me plz
Thx for all the tips/info
=P

 

[Rui]

Spell-related threads go on the Spells and Systems forum.
~Thread Moved

 

[Altazen]

1. Make an aura that affects everyone, and use a custom buff.
2. create a trigger that activates every .01 seconds, picking a unit matching the condition that it is undead, creating a unit with a modified heal ability (no manacost) that belongs to the picked unit, add an expiration timer, and order the dummy to cast heal on the picked unit.

It's rough, but I'll try to find better combos. If you use this, it's more likely your description will be "The Stone's vampiric properties give a random hit point regeneration rate to all nearby undead units."

now... about the evasion... I think it's possible in JASS, but I'm no pro at that...