Special ideas for mobs, special abilities, on heartbeat, death etc

So I'm looking for ideas to juggle around pertaining to monster special abilities. As you know I'm quite fond of these and use them pretty liberally on various mobs I've already put into badlands. I've come up with a few more recently that I'm going to be implementing soon but I'd like to hear from some people who might have things I haven't thought of or heard of.

Some examples are:
Grave Titan, spawns zombies every round since it's basically a walking cemetery.

Tanar'ri, teleport to fleeing targets.

The new earth elemental mob which splits in half into two smaller elementals, and continues doing so until they're about the size of kittens.

Lightning azers which are balls of lightning that shoot our an aura which damages nearby enemies every second.

Negative energy elementals which explode on death and deal AoE negative damage to all nearby enemies.

These are just some of the major and most obvious ones.

I would like to see wandering patrols of militia outside of towns as well as wandering bandits, possibly with morale failure at near death?

Could make for some interesting escort missions too, protect someone across a long map of spawns.


Would really like to see a drow city somewhere in the underdark that you can either go in and trade with or war against, like it would sent out waves of guards and priestesses unless you make some peace offering at the gate, and if you get through you can butcher the whole city right up to the high priestess