Dwarfing the Earth Spacedock, this unknown cigar-shaped probe came to Earth in order to contact members of the long-extinct humpback whale species in the movie Star Trek IV: The Voyage Home.
Everything in its proximity is drained of power and the sheer amount of energy contained in the broadcast began to vaporize Earth’s oceans and ionize the atmosphere.
It is one of the largest vessels ever encountered by Starfleet, measuring at roughly seventy kilometers (43 miles) long.
“Most unusual; an unknown form of energy of great power and intelligence, evidently unaware that its transmissions are disruptive.”
– Spock talking about the probe, 2286 (Star Trek IV: The Voyage Home)