A Sea slug (Opisthobranchia alucinor) is any one of a species of slug-like creatures that are able to control the minds of humans and other living beings by latching onto them. However, they are not too fond of heat, and their victims will pass out if they're exposed to enough heat. They are ruled by Mother Mallum.
Varrock Museum has some sea slugs on display in its Natural History department, which is in the basement. The Apothecary in southern Varrock also seems to have a sea slug pickled in a jar. Whether this will have any future importance is unknown.
The sea slugs were somehow caught by the fishermen on the Fishing Platform and brought aboard. The sea slugs then attached themselves onto the fishermen and possessed them. Victims of sea slugs have a sickly yellow skin colour.
Witchaven EditThe next step in their plans was to free their leader from the prison in which the Temple Knights had sealed them a few hundred ago. They arrived at Witchaven when Kennith got mad at Kimberly for losing his toy train. Mayor Eustace Hobb announced he would be renovating the shrine to the west.
Soon villagers began to become possessed and the Temple Knights of Falador wanted to know why. Investigating, the adventurer discovered their plans of releasing Mother Mallum, but was tricked into assisting them. However, the adventurer managed to kill the slug prince before barely escaping Mother Mallum's possession attempt.
As for the rest of the population of Witchaven, they were possessed and the town became the first in RuneScape to fall to the sea slugs. The villagers are now mining for rubium.
It seems as though the Temple Knights did not wish the danger of the sea slugs to reach the public, as the display in Varrock Museum describes them as "harmless". But if you ask for a lecture on the sea slugs, a natural historian will tell you that ' Researchers kept vanishing and hence they could not research much about the sea slugs.
As of Salt in the Wound, all of their victims are now free, although their exact fate is unknown.
It is revealed in the Hunt for Red Raktuber quest that the sea slugs are now also attempting to control the Penguins. Captain Marlin, the Captain of the Red Raktuber submarine, has been taken over by a sea slug, resulting in his insanity and obsession with the sea. Captain Marlin tells the player that he plans to eventually plant a sea slug on the rest of his crew, followed by the entire Penguin species and the entirety of Gielinor.
- Captain Marlin
- Col. Jake O'Niall
- Mayor Eustace Hobb
- Brother Maledict
- Bailey (only during Salt in the Wound)
- Almost the entire population of Witchaven
- Almost all the fishermen at the Fishing Platform
- The Sea Slugs' ability to take over a human's mind, basically turning them into mindless zombies, is very similar to the headcrabs of the Half-Life series, the Yeerks of the Animorphs series, The Flood from Halo, the brain slugs of Futurama, and the neural parasites of Star Trek: The Next Generation (as all of these life-forms control people through mind-control).
- The sea slugs also feature in the FunOrb game: Armies of Gielinor, as a Zamorakian unit that can control an opponent's units.
- The Sluglings encountered during Rum Deal are likely young sea slugs, as Captain Braindeath says they are related to them.
- Its likley they are based heavily around the Goa'uld from Stargate SG-1, alien parasites that take over the mind and body of human hosts. Like the Goa'uld, they can prolong their victims' lifespan; Mother Mallum has been using the same "husk" for over 1,000 years.