I was in fortress mode making an adventure fort for adventure mode, and I had forgotten to take an anvil with me on embark. I started noticing that several cave people started bursting into flames, but I ignored it thinking it was some cave people fighting fire crabs or something that escaped the magma. So, while waiting for the trade caravan, a forgotten beast appeared! Gasp!
A fire breathing llama covered in scales by the name of Ospun! I was unconcerned, however, because my fortress was entirely enclosed as there was no entrance to my fortress from the caves, since I walled it all in. So, I watched the forgotten beast roam through the caves until he encountered batman, who had splintered into multiple copies of himself!
I thought to myself, "Ha! Those batmans are going to get destroyed by that forgotten beast! He breathes fire!". Well, at least I got the fire part right. Ospun breathed his deadly fire and set several of the batmans on fire, but that did not stop them from charging into the llama with their little spears and blowguns. They fought for about a month without stopping.
This was when I thought, "How come those bats aren't dead yet? It's a giant llama breathing fire!" That's when I looked at Ospun's description and got flooded by a giant screen of red. Fractures, bruises, cuts. However, on his wounds page, everything was only yellow, so that meant he was not very badly wounded. Except for the fact that his blood was EVERYWHERE. At the end, the batmans stabbed and shot (closer to poked and tickled) Ospun so much with their wooden spears and blowguns that he died of cumulative damage, the only casualties the tribe of batman receiving being 2 dead and a broken ankle. Also, through the entire battle, there was one batman who just sat there in the corner eating cave fish.
he's the giant LTL;DR: A giant fire breathing llama attacked my fortress and was killed by batman armed with a spear and blowgun