Ambiguous images or reversible figures are visual forms that create ambiguity by exploiting graphical similarities and other properties of visual system interpretation between two or more distinct image forms. These are famous for inducing the phenomenon of multistable perception. Multistable perception is the occurrence of an image being able to provide multiple, although stable, perceptions.
As a child I’ve always seen funky teeth in the black/yellow Batman logo. It took quite some time before I saw a bat in the negative space.