Walking out of a screening of Cowboys & Aliens, I couldn’t help but think that when the film was a western, it worked, and when it was to do with aliens, it didn’t. One of its faults, to my mind, was that it relied on CG monsters to try and intimidate, scare and interest its audience. And for my money, the computer generated aliens managed to do none of those things.

I’d had a similar reaction this summer to the last act of Super 8, and it got me thinking: has there ever been a point when a CG monster has been scary in any way whatsoever? The closest I could come were some of the dinosaurs in the original Jurassic Park (they weren’t outright terrifying for me, but they did generate convincing tension). But there’s been nothing to match the impact of more tangible creations, in the eye of the camera itself.

I think back to the monsters and aliens over the years that have genuinely managed to unnerve me. The alien in Alien and Aliens (although not the computerised ones that followed in some of the sequels). The Thing. The zombies of George A Romero's movies.

What most of those have in common is that they were real, physical effects, rather than generated by computer. I’m not sure whether that’s coincidence or not, as there’s an argument that, over the years, we’ve all become a bit desensitised to aliens and monsters anyway. Television shows throw them out with alarming regularity, and that means on the big screen, it’s becoming harder and harder to impress an audience.

The last aliens on the big screen that I thought worked were those in the much-maligned Skyline, simply because visually, I bought them. But scary or intimidating? Not at all.

Maybe this is an art that the movies have lost. Certainly, the ability of computers to bilge creatures onto the screen means that restraint has all but gone out of the window. The notion of only letting us glimpse at a creature isn’t gone entirely, of course, as Cloverfield pretty much made a film out of that. But in that example, and many others, when it came to the big reveal, the product of the special effects team was really quite underwhelming. You could say the same of Frank Darabont’s The Mist, too.

I put the question out onto Twitter, as to what movie creatures and aliens genuinely put the shivers up some of our followers. Pretty much every answer, with a few exceptions, was of a physical creation of sorts. So we had The Creature From The Black Lagoon. Lots of people citing The Thing and Alien. The Blob. The Incredible Shrinking Man. It. A quick shout for Candyman. The reavers from Serenity, and the zombie lepers from The Fog. The Pale Man from Pan’s Labyrinth, too (fantastic call, that one).

At the heart of nearly every one of those? Someone in a costume, on a movie set.

I do think, though, that CG can still be used to scary effect, it just has to be deployed very carefully. Look at the low-cost, highly-effective glowing teeth effect that Joe Cornish applies to Attack The Block. There’s no massive computer-created face or anything. Just an adherence to a simple horror dynamic, made possible through a computer. I’d also suggest that Toy Story 3 proved you can make genuinely terrifying horror movie characters with computers. Two of the creations in that film still manage to put the chills up me.

But there are a small handful of exceptions. And I can’t help but wonder if the movies’ skill at scaring us with monsters and aliens has all but dissipated now. In fact, if anything, it’s the small screen where ingenuity still rules. Doctor Who’s weeping angels, and the Silence, are convincing, and have the ability to get under your skin. I didn’t come close to reacting like that in films such as Super 8, Cowboys & Aliens, Clash Of The Titans, Transformers, Signs, War Of The Worlds, I Am Legend, Species, Resident Evil… well, you can fill in the rest of the list for yourself.

What most of these films had in common, ultimately, was that each had a computer generated foe (or foes) that, with the possible exception of Super 8, I didn’t give two hoots about, and, crucially, got no pleasure from watching. In some cases, it was like watching the showreel for a computer graphics expert. Technically brilliant, but with entertainment removed.

Creating genuinely scary creatures and monsters is hard work, and requires a writer and director who know what to show, and what to not. That in itself is a tough skill, and if we’re being circumspect, then there aren’t too many examples from the 70s, 80s and early 90s, before computers took hold, to cite. But I find it interesting that the ones that really stick in our minds – and The Thing and Alien are the names that keep cropping up – were a product of brilliant film makers knowing just how to make the most of what they had.

Thus, computers can’t be blamed altogether. But also, the search for a genuinely scary CG monster on the big screen continues. On the evidence of how aliens are treated in the likes of Cowboys & Aliens, it’s set to go on for some time to come.

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