This DF King Kong...a bronze colossus instead of Kong would work, yes?
or just a ridiculously huge gorilla...
If'n you'll excuse me I now have a replica empire state building to construct, and an exceedingly dangerous gorrila to capture.
P.S. would gorilla tied up with restraint linked to lever in bottom of tower, then with a meeting hall at the top cause the Gorilla to path up the tower?
Maybe siege engines / marksdwarves able to fire on meeting area so gorilla can be killed once up there. and maybe some kind of bridge-a-pult to get the body falling down the tower....
You'd need to build that sucker on a really, really tall mountain. Otherwise, you wouldn't be able to build more than 50 stories or so, remember. Said mountain would also have to border on a savage jungle area, to have access to the gorilla in the first place.
Also, you'd need some sort of plan to keep every damn dwarf in the fortress (and the cats) from saying, "Oh, look, a nice new meeting hall with absolutely no [SIZE:200] gorillas whatsoever!" and subsequently stop partying and zerg rush to the top of the Empire State Building. You'd also need a plan to keep there from being cat corpses every two feet as they run to check out the new meeting area.
The Gorilla at the bottom of the tower with a meeting area at the top... You'd probably have to make it so that the meeting area was close to it and that, once again, no hapless stragglers were in the tower, but it could work (if wild animal's pathing is treated like a siege's, which I don't think it is). Also, I'm not sure how wide wild animal's "aggression radius" is, so you'd want to restrict pathing.
A better, more dwarvenly way to get the body falling would be marking a garbage dump at the top of the tower and one tile off, then marking the body for garbage dumping, making it so that the dwarf nearest to the corpse literally
throws the huge dead gorilla off the Empire State Building. Commence head-scratching on how a [SIZE:6] creature could do that to a [SIZE:200] gorilla.
Of course, this is made all the more dwarvenly when it turns out THE EMPIRE STATE BUILDING IS MADE OF OBSIDIAN AND SURROUNDED BY A LAKE OF MAGMA WITH FREAKING LAVA FOUNTAINS GUSHING OUT OF IT.
Cue "fun."
P.S. The ballista probably wouldn't work, as you'd need to build a platform on the same z-level. Of course, with a crossbow dwarf you'd need that too... I know! Get a champion hammerdwarf and station him at the top of the tower. When the gorilla comes, smash him off and down below! It takes care of two problems at once.
Just watch out for rampaging [SIZE:200] gorillas walking around in the jungle in the meantime, and you should be fine.