Simple Spell... Help!

Simple Spell... Help!

Okay I need to know how I would add a tigger that "Upon death caused by this skull, create *unit*"

The spell is a modified Arial Shackles with the theme of "The wizard attempt to rip the skull out of the being, if succesful, a floating skull is created to serve the master".

I already have a skull made, now all I need is a trigger that says IF the unit dies, a skull is born.

When a unit dies, detect whether the unit had the buff. If it did, replace the dying unit with a skull.

~The_Raven