Last week's entry on How To: Stop A 500 Foot Monster seems to have struck a chord, judging from the number of suggestions for the best military hardware to take down rampaging Cloverfield-type beasts in our urban centers. Several new options were put forward which deserve some serious consideration – ones we'll be forwarding on to the secret monster-stopping divisions of the various defense ministries.

First there were the traditionalists who want to use standard anti-tank kinetic rounds. One version of this takes us back to King Kong, only instead of Curtiss F8C-4 biplanes you have A-10 Warthogs strafing the beast with their 30-mm GAU-8 cannon. This would be fine against smaller creatures, but a 500-foot beast is liable to have a protective covering measured in feet. The GAU-8's projectilespenetrate less than three inches of armor at close range (69mm at 500 meters, in fact) . They are effective against heavy tanks because they can go through side, rear or top armor, but with our beast I don't think they'd get through the skin. As someone once put it: you're going to need a bigger boat. (Or something like that).

The 120mm M828A1rounds fired by M1 Abrams tanks are tremendously effective against armored vehicles, but the round itself is still basically just a big dart made of depleted uranium with no explosive payload. It's about 20mm in diameter and a metre long, so it's equivalent to shooting a human-sized target with a needle about 0.2mm diameter: it would take a lot of them even if the round went deep enough to hit a vital organ.

Some put forward the Navy's new electromagnetic rail gun , which might offer a more powerful option, but it's still a ways down the line. Kudos to MachineMk2 for suggesting the kinetic LOSAT missile. Otherwise known as the MGM-166 Line Of Sight Anti-Tank missile, this delivers a kinetic punch about five times more powerful than a tank round. Equally importantly, it is mounted on a Hummer, so it's both air-portable by helicopter and fairly easy to drive around the streets of New York. Deploying heavy tanks in central Manhattan in a hurry was always going to be a bit of a headache.

(This type of approach assumes that your monster actually has vital organs. Although movie monsters are usually some sort of vertebrate – as far as we can tell – screenwriters might throw a curve ball with something lower down the scale like The Blob. Creatures like man-of-war jellyfish, sponges and hydra are not centrally organized and this makes them very hard to kill. Sponges can even reassemble themselvesafter being broken down into individual cells. Shooting anything like that would be a waste of time.)

There were a few suggestions for the Active Denial Systemor "pain ray." This shows the right kind of instincts: against sci-fi monsters, a sci-fi ray gun feels about right. Unfortunately, the depth-of-penetration problem is even more severe here, as it is carefully designed so that the beam only goes through about 1/64" of skin. In fact this is one of the ADS' selling points, that it will only have surface effects. I have previously described some of the more unusual testsof the Active Denial System, including experiments with military dog teams , but I don't think they ever tried it on anything larger. It's highly unlikely you could get any sort of a reaction from a very thick-skinned monster without redesigning the system from the ground up using a beam with a longer-wavelength.

(Previous non-lethal weapon developers were more adventurous, and went so far as testing LSD on an elephant - unfortunately, the elephant died. Maybe there's some monster-killing potential there?)

Then there is the extreme option: "I say we take off and nuke the site from orbit. It's the only way to be sure," suggested Ripley, apparently speaking from experience. The problem here is the tradeoff between the damage done by a 500-foot beast and the devastation likely to be caused your nuclear warhead. A 150-kiloton warhead would almost certainly do the job. But it would be very unpopular with local residents, as this simulation of the effects on Manhattan of such an explosion shows - hundreds of thousands dead and injured. What is needed here is something as small as possible – the suggestion of using the 1950's Davy Crockett nuclear bazooka sounds pretty smart, with its selectable yield from 10-20 tons to half a kiloton. Unfortunately, they just don’t make them like that any more: in 1991 the US took the decision to remove all ground-launched tactical nukesfrom the arsenal, and the 1994 Furse-Spratt amendmentprohibited the development of any new warheads of less than five kilotons. There is still a stockpile of air-launched tactical nuclear weapons, but I don't know if there's anything quite suitable for tackling monsters in urban theaters.

It's possible to de-tune nuclear warheads and reduce their yield. But doing this in a hurry is liable to result in a very 'dirty' explosion with a large anount of radioactive fallout. And that would probably only mean more monsters…