Transformation scenes have always pulled in the crowds. Victorian theatres were packed with hidden stage machinery designed to turn pumpkins into princesses, or make entire castles materialise under the gaze of the astonished audience. Even before the days of smoke, mirrors and Pepper’s Ghost, Shakespeare shifted some shapes of his own when he turned the hapless Bottom into a braying donkey.

Over the years, the movie business too has offered up all manner of magical metamorphoses. Early experiments involved simply stopping the camera mid-shot and replacing one actor with another. As filmmakers perfected optical tricks like dissolves and wipes, transformation effects became more subtle. At the same time, developments in make-up and mechanics permitted ever more elaborate illusions to be played out right in front of the lens.

Given the extraordinary variety of shapeshifters that have writhed their way across the silver screen, it’s hard to choose a favourite. Here are three of mine:

Dr Jekyll and Mr Hyde TransformationDr. Jekyll and Mr. Hyde

In Rouben Mamoulian’s 1931 adaptation of Robert Louis Stevenson’s Dr. Jekyll and Mr. Hyde, Fredric March plays a brilliant physician who creates a potion that unleashes his monstrous alter ego. In the central transformation scene, we see March change from gentle Jekyll to homicidal Hyde in a single shot. The special effects for this sequence were masterminded by Wally Westmore.

The master shot begins on Jekyll’s face, which contorts in agony as the potion takes hold. The flesh around his eyes darkens and his cheeks appear to sink. The camera pans to Jekyll’s hand clutching the arm of the chair on which he’s sitting, before returning to his face. Each time this move is repeated, the actor’s face has changed further. By the end of the shot, Jekyll has become Hyde, complete with unruly hair, an upturned nose and a set of ferocious teeth.

It’s easy to guess how some of the gross changes were done, with unseen artists altering March’s face while the camera was pointed at his hand. Less obvious – and infinitely more clever – is the way layers of different-coloured make-up were applied to March’s face, with each layer revealed in succession by switching coloured filters in front of the lens. Photographed in black and white, the shifting colours read as fluid changes in the actor’s physiognomy. As with all great illusions, the changes happen right before your eyes.

An American Werewolf in London TransformationAn American Werewolf in London

Until An American Werewolf in London was released in 1981, filmmakers had relied mostly on clever cutting and nifty optical dissolves to turn their leading men into lycanthropes. Director John Landis changed all that when he briefed Rick Baker to create what still stands as the best werewolf transformation ever.

In an Oscar-winning tour de force of animatronic and make-up effects, Baker shows us every painful contortion of David Kessler’s body as his anatomy reshapes itself from human to lupine form … while all the time Bobby Vinton sings Blue Moon. Using home-made pneumatics, a super-stretchy urethane-elastomer flesh substitute called Smooth-on #724 and upwards of ten operators, he reshaped actor David Naughton into a horrific, hairy beast.

I hardly need describe the sequence, so iconic has it become. But I will remind you how everything – the extending fingers, the vertebrae snapping out of Naughton’s spine, the juddering extension of his jawline into the muzzle of the werewolf – plays out in bright daylight in an ordinary London apartment. No horror-movie lighting here, no shadows to hide the joins. I’ll also point out how successfully Baker’s effects integrate with the editing and sound design. The result is compelling storytelling, agonisingly presented from the poor protagonist’s pain-racked perspective.

(1981 was a bumper year for werewolves, with Rob Bottin’s decidedly more funky transformations in The Howling giving Baker a run for his money. In my opinion, Baker wins this one hands down.)

Dark City TransformationDark City

Shapeshifting isn’t just about fantasies of the flesh. In Alex Proyas’s Dark City, released in 1998, entire city blocks are on the move. Yes, I’m talking about a marvellous metropolis metamorphosis!

Now, I know there are still lots of you out there who haven’t seen Dark City. For that reason, I’m going to avoid spoilers – this is one of those films you really do need to see without any preconceptions. All I’ll say is, if you like Blade RunnerThe Matrix and Inception, and don’t mind a film that’s a little rough around the edges, this one’s definitely for you.

In Dark City‘s transformation sequences, whole buildings twist and turn. A brownstone tenement elongates to become a skyscraper. A mall becomes a church. A moody and vaguely gothic skyline rearranges itself in an ballet of architecture. Why does this happen? In story terms, I’m not telling you, but I will reveal that the visual effects are the product of what at the time was boundary-pushing CG and miniatures work, created by Sydney-based DFilm Services, now part of Animal Logic.

Okay, what was boundary-pushing in 1998 looks a little dated now. The morphing of the buildings, extraordinary as it is, is somehow just a little too smooth and mathematical. But I don’t care. The concept is so visionary, and the execution so brave and ambitious, I can forgive the sequences – and indeed the film – any minor shortcomings. And that’s all I’m prepared to say, other than to encourage you to dust off that DVD (make sure it’s the superior Director’s Cut) and give Dark City a second look. If you’ve never seen it before, prepare yourself for a treat.

Well, I’ve shared my own trio of transformations. Now it’s over to you. Have you got a favourite shapeshifter?