Oh boy do I have a story.
I decided to generate a world with lots of evil. Well, I succeeded. Tons of megabeasts, tons of evil land... basically there's a single swatch of good mountains, forests and plains where the one elvish and dwarvish civilization have settled.
My civilization got conquered by one of the three goblin civilizations on this continent fairly early on, but one of the elvish forest retreats (the elvish civilization itself got wiped out by undead dragons and a bronze colossus) is apparently a part of the dwarvish civ. Interestingly, Legends does show a dwarf started living there a few decades after its destruction... but also that said dwarf was killed a few years later.
Anyway: world full of megabeasts, lots of goblins, dwarves who may or may not exist. Yay.
I embarked in haunted badlands and immediately began digging into the nearby hill. I even got all my stuff moved in before evil rains or clouds appeared. Sadly, that's when the undead camels struck.
It was a massacre. Five dwarves, most of them armed and one even armored, fought three of the aggressive artiodactyls. Net result: five dead dwarves, one dead camel. My expedition leader (not the original one, just some guy who got the title when the real one died) was running around screaming, and my surviving miner had walled himself in deep underground.
Turns out the camels couldn't spot Urist McScreamy from their position, and they left. This was great because it meant I had all of my embark stuff now: I wasn't looking forward to trying to keep a lone, equipment-less miner dwarf in an evil desert fed.
My two dwarves quickly finished the almost-completed wall, sealing them off from the outside world. Food was moved further in, corpses stacked in an anteroom. Strangely, none of them seemed to be animating even after several months, so I figured this part of the embark wasn't reanimating.
With my two yaks (who had somehow survived the camel attacks) getting hungry, I decided to slaughter one. Bad idea. Apparently the only reason those dwarves weren't getting back up was that the camels had mangled their bodies. A cleanly killed yak, though? That one's gonna rise.