The term antagonistic expresses sentiment of or relating to a thing that antagonizes. The  opposite of the word protagonist, it connotes someone who is against something. An antagonist intends to stop something from happening. The word typically has been assigned a negative connotation, as it is associated with bad behavior, that is destructive to something or someone. An antagonistic text would most likely be opposing or criticizing something else.

EX - The evil villain opposed the good protagonist.