- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
Infection contained in thorns on the large predatory vines of Surata IV, designed to fatally attack the neural systems of warm-blooded animals so as to enrich surrounding soil with their decayed remains. Considered neither a virus nor a bacteria but with elements of both, the microbe in one case entered Commander Riker's left calf just below the knee to infect the great cyatic nerve and rapidly multiply. By fusing to the nerve at a molecular level, the microbe defied conventional surgery and stumped the transporter's biofilter, causing no damage but impeding neural function leading to paralysis and eventual brain infection. Its growth rate doubled when fed endorphins released when erotic dreams and emotions were stimulated; it decreased with chemicals stimulated by feelings of survival and near-death.