The Water Demons, appeared in the episode, "The Tale of the Water Demons". It is unknown who portrayed them.
Water Demons are the angry spiritual zombies of men and women who died at sea in sunken ships and were robbed of their valuables. They
are soaked to the bone in water and usually covered with green slime that often drips as the move.
When they find their new victim they leave their mark on them, which are green slimy hand prints. When they discover where the location of their grave robber lives, they are always summoned when he or she has fallen asleep. This is because the grave robber, has been cursed by the sea. Therefore when he or she falls asleep the sea summons a cloud of dense pea soup fog and slowly a group of them emerge.
For as long as their victim is asleep, they will emerge further until they'll reach it's home. Then when given they chance they will take their revenge for being robbed. What they will do, is they will take their victim with them and drown them at the bottom of the sea.
In the year 1964, a luxury Yacht named the Del Rio hit the rocks and sunk to the bottom of the sea. There were no survivors. Then a Sea Captain named Abraham Westchester swam to the bottom and broke into their sunken yacht. He was famous and wealthy for looting pillaging sunken ship around the world, and wasted no urge to do the same to their ship.
The most interesting fact, was the Del Rio crashed and sunk into the ocean that was in the backyard of estate of Captain Westchester. The day he looted their ship of their valuable was the day he was cursed by the sea. Then every time he would fall asleep, they would emerge in pea soup fog and slowly come after him. For many year he was able to avoid them by timing his sleep and hiding behind a false wall. Also, he tried to dump all of their valuables back to the ocean, but it didn't work because he had traded some of it.
Then year later in 1994, Shawn Mackenzie had just delivered coffee with his cousin Dean Wilson to Captain Abraham Westchester. The two of them didn't believe the Captain at first when he told them the story about them and why they were after him. When they left Shawn stole one of their solid gold pocket watches from the Captain's collection.
Then later that night, Shawn ran away from his Uncle's house and ran over to the Westchester Estate. He went to sleep outside in a the hammock. Then just as he went to sleep, the Captain fell asleep too. Then in no time at all, they emerged from the ocean. They could immediately tell Shawn stole from them too and gave him their mark. They cornered him at the hammock. While dripping water and slime onto him they kept angrily muttering the phrase "Grave robber" to him. Shawn kept on yelling and screaming for help.
They came after Shawn as he hid inside a shed. Then after honking an air horn several times, Captain Westchester finally woke up. Then they instantly vanished back to the sea. Then the captain and the two boys decided to load up a boat with the items Captain Westchester got in exchange and give it to them to make up the difference.
But Captain Westchester got knocked out cold and Dean's glasses fell into the ocean. So Shawn made the trip to the buoy instead. Then as Shawn arrived they all swam up and held onto the rim of the boat. They were all furious and they kept vigorously trying to knock the boat over. Then after Shawn tossed in the last item they returned to the bottom of the sea.
Then just as Shawn returned to the dock to celebrate, one of them pulled his cousin into the water head first. Shawn screamed to them to let him go. Then he realized he still had the pocket watch he had stolen earlier. He threw it in and apologized profusely for himself and on the Captains behalf. Then Dean was let go, then as a thank you, they also returned Dean's glasses. Then the boys realized they were now at rest at long last and the Captain was happily informed that he could sleep once again.