Metalepsis (from Greek μετάληψις) is a figure of speech in which a word or a phrase from figurative speech is used in a new context.
In narratology (and specifically in the theories of Gerard Genette),
a paradoxical transgression of the boundaries between narrative levels
or logically distinct worlds is also called metalepsis.
“deliberate transgression of the threshold of embedding” resulting in “intrusions [that] disturb, to say the least, the
distinction between levels.” It produces an effect of “humor” or of “the
fantastic” or “some mixture of the two […], unless it functions as a
figure of the creative imagination […]” (Genette 
1988: 88). Genette (2004) also argues that not only is metalepsis a
violation of the separation between syntactically defined levels, but
also a deviant referential operation, a violation of semantic thresholds
of representation that involves the beholder in an ontological
transgression of universes and points toward a theory of fiction