Returning Projectiles

[Malkav04]

How would you suggest I make a targeted abillity, like stormbolt, but where the projectile is emited from the target and not the caster?
Or a stormbolt like the spiderattack abillity, that hits the target and then returns.

 

[GhostWolf]

How would you suggest I make a targeted abillity, like stormbolt, but where the projectile is emited from the target and not the caster?

You will need to create a dummy unit at the target's location and order it to cast the spell on the caster.

Or a stormbolt like the spiderattack abillity, that hits the target and then returns.

Use their ability ?