The giant crane forms part of the Topshop Playland, which encompasses a Twitter-powered vending machine as well as Ms Pac Man, Zoltar and coin pusher machines.
The crane is located in the main window of the store, and customers can control it via Twitter to win Topshop prizes.
The activation will take over the central London flagship until Sunday (31 May).
Tom Scott, managing director, CreateLondon.co.uk, said: "We have been working with Topshop for a number of months now, offering new and innovative ways to integrate social technologies into experiences to make them more interactive for the consumer but also deliver valuable social reach for the brand.
"Our goal is always to integrate social technologies seamlessly, built into the experience from conception. The giant claw is a real showstopper that typifies this and will drive lots of positive social currency for the brand."
Rachel Thomas led the creative aspects of the activation, meanwhile Family LTD was responsible for the production.