|Launched:||500,000 years ago|
The Cetacean Probe was a device created by a distant race of cetaceans to search for other species. In its years of exploration it encountered many worlds and species, including the Borg, who attempted to assimilate it. They failed, but did succeed in damaging its crystal memory. (TOS novel: Probe)
In 2286 the probe returned to Earth to try and re-establish contact with the Humpbacks, which by that time had been driven to extinction. When it received no answer, it began to vaporize Earth's oceans. Realizing that the only way to stop the probe was to answer it, Admiral James T. Kirk of the HMS Bounty traveled back in time to 1986 and retrieved a pair of Humpbacks; George and Gracie, to respond to the Probe. (TOS movie, novelization & comic adaptation: Star Trek IV: The Voyage Home)
A year later, the crew of the USS Enterprise-A encountered the Probe again during a joint Federation-Romulan archaeological expedition. The two parties were able to open a dialog with the Probe, which had been uninterested in humanoid life - seeing them as "mites." Spock was able to determine that the Probe was missing large portions of its memory due to an encounter with a group of aliens - possibly the Borg - and that these aliens were responsible for the disappearance of those who created the probe in the first place. Due to this dialog, the Probe learned that if it sent out transmissions too loudly, it would damage humanoid technology. (TOS novel: Probe)
In an alternate timeline in which Spock died in childhood and Kirk died while saving his son David Marcus from the Klingon Commander Kruge in 2286, no mission was undertaken by the Enterprise crew to retrieve a pair of Humpback whales from Earth's past. Instead, the probe ravaged Earth unopposed for a period of about a week before finally moving off. In the aftermath, Earth's atmosphere was ionized, destroying the ozone layer, and torrential storms rained down across the planet, blocking out the sun and preventing agriculture.
Dr. Carol Marcus attempted to use a less powerful version of the Genesis Device to restore the Earth's atmosphere to its previous state; however, the Klingons chose to use the opportunity to invade Earth. (TOS - Myriad Universes novel: The Chimes at Midnight)
In the mirror universe, Spock took the ISS Enterprise back in time to 1986 so as to retrieve some humpback whales who could then respond to the probe. When the two whales were brought back and deposited in Earth's ocean, they interacted with the probe and were transformed into huge armored leviathans, traversing the tsunami-swept oceans, and destroying entire coastal cities. Eventually Spock found a way to enter the probe and shut down its computer core; however, the damage caused by whale-beasts' rampage, as well as the probe's transmissions, left much of Earth's industrial capacity in ruins, a forewarning of the imminent collapse of the Terran Empire. (Decipher RPG module: Through a Glass, Darkly)