The Beast of Bottomless Lake appears in The Scooby-Doo Show episode "The Beast Is Awake in Bottomless Lake". The beast was the disguise of Julie, a gold smuggler who used it to terrorize a village around Bottomless Lake in Canada.
The beast was a large human-fish hybrid creature. It was green with a yellow belly, dorsal fin and glowing eyes.
Powers and abilities
The beast disguise gave Julie exceptional swimming skills and the ability to breathe underwater.
Mystery Inc. arrived on a fishing trip and found the village deserted, except for the owner of an convenience store, a mysterious fisherman, and Julie. They were told that the lake level was falling, strange blasts filled the night, and mysterious lights could be seen in the Lake.
It wasn't long until the gang encountered the beast. After several chases (including one in which Shaggy and Scooby-Doo were blown up with helium), Fred decided to scuba dive under Bottomless Lake. Shaggy and Scooby stayed behind, as usual, and promptly encountered the beast.
It chased them into the lake and an underwater base. There Shaggy and Scooby found that someone had blasted a tunnel in the lake floor. After getting sucked through an airlock, they were caught in a net by two henchmen. Fred, Velma and Daphne arrived in time to catch the others and unmask the beast, who was Julie. She disguised herself as the beast to cover up the fact that she was shipping stolen gold through the tunnel to her henchmen. Julie and her helpers were then taken to prison.