Anybody who reads "XKCD" is going to love this one...
So, I play a modded DF (Dig Deeper, and a few other mods that add Civs and Creatures) to increase the "Fun" value.
Increased the fun has been...
So I've got this fairly nice fort going, I finally get to about 30 dwarves, survived a few Orc seiges (Read: cut off from world, cowering indoors) and I've got a pretty nice lumberjacking system that allows my dwarves to be safe from the outside world through a system of doors and bridges, while chopping down trees on the surface.
Now I don't believe in cutting myself off from the world UNLESS I'm being seiged by impossible odds, aka Orcs. An Orc raiding party is sighted, everyone is marshalled indoors, and we get ready to survive the winter in the fort.
I notice one of my animals come running into the meeting hall, which wouldn't be considered odd, except for the fact that I locked them all in a cage...
Then I get the message... An animal has been struck down, then another, then another....
I read the report screen "a" and lo and behold someone was letting out all my animals and killing them. I send a recruit to check on the animal pen and he's ripped apart by no less than 6 raptors! SIX! Well this is bad... So I send in my entire military (Consisting of about 8 "trained" dwarves) and then the real weight of the situation hits me...
There are a few more than 6 Raptors that snuck into my fort.... There are more than 10... 20...
30...
40.
Fourty raptors snuck into my fortress without my knowledge right before I closed my fortress off from the seiging Orcs, and the Raptors ripped my fortress apart from the inside... like a spikey haired yellow skinned boy eating a razor sharp Krusty-O. Only with more beards.
All subsequent fortresses have included raptor emergency kits... And a comprehensive raptor self-defense training regimen.