- 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
A large mass of ice and ionized gas, with a large concentration of silithium, detected near the Gamma Quadrant side of the wormhole and not attached to the gravity field of any one solar system. Thanks to the silithium which could cause a cascade reaction, its impact with the wormhole due to gravimetric surges after a premature opening would have caused a permanent collapse of the Prophets' tunnel.