Commuters arriving at Liverpool's Lime Street station were greeted by a 50ft (15m) high mechanical spider clinging to a nearby redundant office block.
The 37-tonne beast heralds the start of a five-day piece of street theatre as part of the Capital of Culture year.
It has been built by French company La Machine, which in 2006 brought the streets of London to a standstill with the Sultan's Elephant.
The spider is believed to be "waking up" on Friday.
It will descend from its current position on the side of Concourse House on Thursday to be moved to the city's new arena, before coming to life on Friday.
The creature will then begin exploring the city later that evening.
It will form part of a huge piece of street theatre throughout the city at various landmarks, culminating in what organisers are calling a "spectacular finish" on Sunday.
Tens of thousands of visitors are expected to flock to Liverpool to get a glimpse of the mechanical beast.
Although an impressive sight, one man told the BBC that it left him somewhat nervous.
"I don't like spiders. It looks interesting, but I really don't like spiders," he said.
Stopping to look at the creature, Jean Evans, of Birkenhead, in Wirral, said: "It's something really different, it's something unique and I think it's going to put Liverpool more on the map."
Another onlooker Dorothy Wilson, 82, said: "I wouldn't like to meet it in the dark.
"They say it's going to walk the streets but I hope I'm not down here when it does."
Billed as one of the highlights of the 2008 Capital of Culture celebrations, La Machine has been commissioned by arts company Artichoke.
Helen Marriage, the producer of the show, said: "It is the kind of show you can dip in and out of. She's here until Sunday.
"It has 50 axes of movement so all of it moves as you would expect an insect to move.
"It is an unfolding story that takes place in all the public spaces in the city using the great buildings as its stage."
The spider is made out of steel and poplar wood and will be operated by 12 people strapped to its frame, Ms Marriage said.
The creature was built in Nantes before being shipped to Merseyside to be assembled in a secret location.
In May 2006, the company's Sultan's Elephant drew an estimated one million people to the streets of London.