Need help with targeting units

[Megika]

Well, I'm making a spell which, when cast, shoots chain lightning at nearby units. I have a dummycaster, the spells, etc. But in the trigger editor, when telling the last created units to use chain lightning on (Unit), I can't find an appropriate target. What I'm looking for is the nearest unit; but a random unit would be fine.

 

[Fluffball]

Set Unit Group = (Units in 750 Radius of Point)
Set Unit = (Random unit from (Unit Group))

 

[Megika]

Alright, that's working fine. Thanks very much. I would rep, but I dunno how

However, I've hit another roadblock: I want to make it so that when an enemy is struck by the chain lightnings, it creates another caster who does a similar thing to the first one. Could I get some advice on how to do this?