CompInitialMentalState makes an animal spawn with a defined mental state

    //A comp class that makes animals always spawn with a mental state

    public MentalStateDef mentalstate;

It is a comp class, so you just add it in XML in the <comps> tag. For example, this makes the skeletons in Vanilla Psycasts Expanded start enraged (like manhunter but only against colony enemies)

<comps>
	<li Class="AnimalBehaviours.CompProperties_InitialMentalState">
		<mentalstate>VPE_Manhunter</mentalstate>
	</li>
</comps>