The Gagosian Gallery's new Bond Street site, which resembles a department store window opening on to a narrow strip of gleaming white space, has once again turned into a toy shop.

First it was Jeff Koons who filled the gallery with inflatable paddling pool toys, which were then revealed as aluminium casts painted to perfectly replicate the original plastic. Now it's Carsten Holler's turn to provide the cute factor: a pink baby hippopotamus lies curled up asleep on the floor like a puppy. Apart from its neon pinkness, it looks surprisingly realistic, creating an urge to prod and stroke it.

Holler's art is all about making you want to interact with it. He was the man responsible for the whizzy slides at Tate Modern's Turbine Hall and he once filled a gallery room with frisbees for punters to lark about with. He's clearly an artist who seeks to inject some much-needed fun into the lives of gallery-goers not used to shrieking with either fear or laughter in a room full of art.

To accompany the hippo Holler has also produced, in collaboration with Attilio Maranzano, a series of photographs of funfairs (pictured) - fuzzy images that have been overlaid with strips of candy-floss colours that seem to vibrate before your eyes. Unlike much of his other work, you could even call these beautiful.

Until Sep 21, Gagosian, 17-19 Davies Street W1, Mon to Fri 10am to 6pm, free.

Tel: 020 7493 3020. Tube: Bond Street