With "regular" textual influence, a text (A) is first created and influences a text that occurs later in time (B). For example, when we read a book written by author Tom Clancy, our understanding of the book will influence ("animate") how we interpret and understand the movie created from the book. This is a cause and effect relationship: the first text is the cause; any influence of this first text on all later or "subsequent" texts is the effect. The influence is deemed "chronological" because it occurs logically in time. The first text influences in ONE DIRECTION all related texts that follow.
However, what if the movie somehow changes our original reading of the book? What if we understand the book's "text" differently after we've watched the movie? In that case...we have something called...
With intertextual interanimation, the influence or animation is TWO DIRECTIONAL. For example, imagine listening to a song (text A) on the radio for the first time. Weeks later, we see a music video (text B) based on that song. The influence of the music video's images and narrative significantly alters how we now understand, appreciate or interpret the song. In essence, we can never return to our original understanding of the song, because it has been forever "intertextually interanimated" or influenced by the music video.