Crossover Wiki:Dream interaction

A dream interaction is when elements from different series interact within a dream or some other non-real plane instead of the reality of their universe. Although a dream is not real, which would usually be considered type 2, if the elements have a normally type 1 interaction, the link between those series would be considered to be type 1.5.

Note that if the elements never interact in the dream, the link would only be type 2.