So I'm trying to figure out what to do here for the original issue.
DO I use useattack plus the weapon's ID or do I use attackwith and the weapon ID or do I use the order ID instead of the weapon ID?

Much simpler, just go into DatEdit, Effect: Ensnare, hook up splash radii to make it aoe.

So you mean look into InfTer suicide attack in dat, change the effect and add the splash radii numbers?
SO I could use plague?

Should be possible, don't see why not since it worked with Ensnare. Just make sure to set the Effect to the same as Plague and match it to Plague's splash (it won't do any damage but it will apply the effect in the same splash).

so the main attack won't do much damage but will just spread the plague?

To the best of my knowledge, yes.

well thaht's slightly disappointing.

You can modify the iscript of plague to include domissiledmg and it should apply the damage of the weapon you're modifying in DatEdit, but I haven't tried this as I wanted my Infested Terrans to just apply the Ensnare slow, not do any damage.

Double posting since I have a question now.

Is it possible for a plugin to do the following:

-Detect when a building is unpowered (no Pylon nearby) and kill it? [bonus points for only killing non-neutral structures, e.g. player-owned or computer-owned]
-Detect when a Pylon is destroyed and kill all units in a small location around it? [bonus points for only killing the owning player's units]

I want this to be possible even in melee play.

Neiv's Teippi can detect and effect both scenarios.

This will be possible even in melee play.

Alright, thank you.

I would like the "pylon blows up and does heavy damage to everything around in it's psi field" thing.