The Eater of Time...

It's gold, features six patented inventions … and has fangs.

The hour approaches. The beast's jaws gape, its tail quivers and then snap! Another minute has been devoured, and the hour strikes with the ominous clonk of a chain dropping into a coffin. The creature blinks twice in satisfaction.

"It is terrifying, it is meant to be," said John Taylor, the creator and funder of an extraordinary new clock to be unveiled tomorrow by Stephen Hawking at Corpus Christi College in Cambridge. "Basically I view time as not on your side. He'll eat up every minute of your life, and as soon as one has gone he's salivating for the next. It's not a bad thing to remind students of. I never felt like this until I woke up on my 70th birthday, and was stricken at the thought of how much I still wanted to do, and how little time remained."

Christopher de Hamel, an expert on medieval manuscripts and Fellow Librarian at Corpus Christi, described the clock as "hypnotically beautiful - and deeply disturbing".

Hawking, celebrated as the author of A Brief History of Time, is returning from the launch of the particle accelerator at Cern in Switzerland to unveil Taylor's sinister vision of his subject.

Taylor is an inventor whose thermostat switch is incorporated in 600m electric kettles all over the world. He first gave £2.5m for a new undergraduate library at his old college, and then offered to create and donate the £1m Corpus clock to the library. The work has involved 200 people, including engineers, sculptors, scientists, jewellers and calligraphers. Taylor regularly flew over in his own plane from his home on the Isle of Man to keep an eye as beady as his creature's on the work.

For all its apparent eccentricity, the clock is based on solidly traditional clockwork - unusual in these days of digital electronic clocks. It has taken seven years' research and construction, incorporates six patented inventions, and is predicted to run for at least 250 years assuming the world lasts that long.

Engineer Stewart Huxley refuses to reveal the secret of its tricks, which include the pendulum occasionally apparently catching and stopping for a heartbeat, and then swinging faster to catch up.

The rippling gold-plated dial was made by exploding a thin sheet of stainless steel onto a mould underwater: none of the team actually saw it happen because the only place in the world which could make it was a secret military research institute in Holland.

The monster momentarily stops the turning dial with its foot to mark the minutes, shown as blue LED lights shining through slots. It was originally conceived by Taylor as a literal interpretation of the grasshopper escapement invented by his hero, the Georgian clockmaker John Harrison whose fabulously accurate mechanisms solved the problem of establishing longitude at sea.

The creature, modelled by sculptor Matthew Sanderson, was inspired by medieval armour and gradually became more ominous: part-lizard, part-stag beetle, a Chronophage – time eater.

Although the entire mechanism can be swung inside the building for cleaning and maintenance, from next weekend it will be a public clock on a street corner in the old doorway of the former bank, a listed building which became the shell of the library. As the clock was installed over the last few weeks, any time the door in the hoarding was left open crowds gathered, transfixed by the sight of time passing.

The Corpus Clock and Chronophage has been officially unveiled by Stephen Hawking at Corpus Christi College.