I recently had a fort in a haunted biome. The Dwarves were comfortably burrowed into the hill, cut off from the outside world, with a drawbridge to allow the entrance of merchants and migrants. Strategically-placed cage-traps prevented things from getting too out of hand.
The fort had gone along for a year or two, when a Titan (a pterosaur) came. It wandered about for a while, oddly not flying in, before gaining entrance with some merchants. It slaughtered them, and proceeded past my cage-traps unaffected. I dispatched my militia, which made short work of it. I didn't want an undead Titan, nor did I want to pass up the opportunity for Titan-meat, so I ordered my butcher to butcher a corpse (the titan being the only uncaged and unanimated cadaver, as far as I knew.) The corpse disappeared, and I naively assumed that it had been cut-up. I soon learned how wrong I was.
The thing had been taken to the corpse stockpile, from whence it proceeded to rise and begin its slaughter anew. In desperation (and failing to realize that the corpse must have retained its trap-immunity, else it would never have gotten past the stockpile) I sent my dwarves to a little room on a lower lever, past a line of cage traps. There were too many zombies by now, and loosing seven of their number did little to lessen the danger.
Only one dwarf survived, a woodcutter (who had become hardened to seeing his comrades killed,) who managed to fall down the drawbridge-pit. Deconstructing the floor that sealed him in, he managed to make do with the supplies at the nearby Trade Depot. He sealed himself off from the deathtrap that Yoremanners had become, proceeding to mine out a new bunker, in the hopes of eventually welcoming newcomers. Several migrants came, but he died of thirst before he could let them in. It was around this point that the game crashed.
Perhaps one day I shall return and avert the death of that heroic wretch.
Re Kobolds: I can't help but think of them like this-