Sorry for the title, I couldn't resist.
So, I started a 40.05 fort up recently and about 2 years in a Were Elephant shows up. He zipped towards a fisher dwarf and one-shotted him before turning back into a goblin and quickly leaving - and I mean quickly. So fine, I had a green military anyways.
So about a year later, I have two pretty decent squads of hammer and spear dwarves clad in steel for the most part, when he shows up again. So, great, I feel like we're reasonably ready for him and order the two squads to attack and unpause the game. I have never seen something move so fast. The Were Elephant sped across the entire map in literally 6 seconds to my fort's entrance where he promptly exploded a butchery workshop. He then raced inside where my squads began to engage him as my barracks is, of course, near the entrance. I can only imagine what it looked like to the dwarves as a red-eyed, frothing, monstrous elephant of insanity advanced on them at about 100 miles per hour through the wide stone entrance.
I was tense with anticipation at this point getting ready to watch the fight as they engaged each other. The dwarves quickly surrounded the beast and had it pinned up against the wall. The fight continued for a about a minute before I decided to check the report to see what was happening. Fortunately, either my squads were fantastic dodgers, or the were elephant was terribly unlucky in its strikes as it failed to hit any of them once. The dwarves on the other hand were fracturing legs and bones with their war hammers left and right, even exploding some of the beasts body parts into gore. But it was regenerating faster than they could inflict the damage, even parts that were severed or crushed.
On and on the fight went for about a week horrifying any kittens that came near them. The dwarves who were fighting actually started taking breaks to go drink some alcohol and then come back to the fight which was pretty amusing. Finally, after 10 days of fighting, the were elephant turned back into a goblin and ran lightning fast to the edge of the map, where a hunter shot him in the head with a single bolt.
So ended the were elephant rampage.