I'd like to use the Wabbajack effect, the effect that happens to NPCs when the wabbajack is used on them. I'd be using it with placeatme. Problem is I can't figure out the property I need to add to the script. It's not an explosion that's for sure. Help please.

There are a lot of effects involved with the Wabbajack. Which effect(s) are you trying to reproduce? You say you don't want the explosion?

I want to placeatme (well around an NPC) the effect that happens when they are hit by the wabbajack, the part where the actor disappears (disabled I guess, well that is the way I will do it) and in the actor's place appears another actor such as a chicken, cow, etc

This is how the Wabbajack script does that (you can find the script attached to the DA15WabbajackFF magic effect):

targ.disable()			newRefStore = targ.placeAtMe(chicken)

You will have to set up "chicken" as property filled with the appropriate chicken actor. There are other examples in the script too if you want to look it over (mudcrab, sweetroll, etc).