This is Mark Wallinger‘s “Time and Relative Dimensions in Space 2001″, a life-sized mirrored model of the TARDIS from Doctor Who which at certain angles seems to blend into its environment. It was exhibited at The Hayward Gallery in February 2009.
“I have always been interested in how we define and are defined by thresholds and boundaries, the events of history. The works in the exhibition use illusion, artifice and dislocating devices to look at our accidental time and place in the world afresh.” - Mark Wallinger
(via Mark Wallinger’s TARDIS | Retronaut)