The "Rage Virus" is a fictional pathogen featured in the movie 28 Days Later. It causes extreme aggression and loss of rational thought in infected individuals, turning them into violent, zombie-like creatures. The virus spreads rapidly through blood and saliva, leading to widespread chaos and societal collapse. In the film, the outbreak begins when animal rights activists release infected monkeys from a laboratory. The virus's effects are depicted as instantaneous, with victims becoming aggressive within seconds of exposure. The narrative explores themes of survival and the breakdown of civilization in the face of a viral epidemic.