We have proposed a scheme and presented the first experimental demonstration of acoustic illusion, by using anisotropic metamaterials to manipulate the acoustic field near boundaries of arbitrary curved geometry. Numerical simulations and experimental results show that in the presence of an illusion cloak, any object can be acoustically transformed into another object. The designed illusion cloak simply comprises positive-index anisotropic materials whose material parameters are non-singular, homogeneous and, moreover, independent of the properties of either the original object or the boundary.