I want to try making a frenzy poison of some kind, but is this even possible? I noticed the "self" box is disabled in the magic effects dialog window for Frenzy. It also doesn't seem possible to create a new magic effect either. Are they hard-coded into the engine?

If it's not possible to use this effect, would it be possible to script something similar? E.g. make a poison with a script effect and use a script that causes the NPC who used the poison to become hostile to everyone and start a fight or something?