There was a man who originally held the name Marine Marauder. He had the ability to have mental control over sea life like Aquaman. A "lowly" marine biologist upset with his station in in life, when the future Marine Marauder discovered a technological means to control air breathing marine life he decided to hijack a crucial shipment of vaccine for ransom. He was opposed and defeated by Aquaman.
Dr. Marlene Simmonds had also been a very competitive person. She had to the best in all respects, and beauty simply wasn't enough for her. After developing a way to control sea-life, she invested some of her brothers money, and took a cruise, intending for it to be her first job, to take the possessions of the passengers while they were at sea. An act of piracy. However, she didn't count on the Outsiders being aboard to disrupt her plans. During a dance, after showing Looker up all day by out-competing her, Looker telepathically "probed" her, finding that she was unable to read her thoughts.
Marlene, then confronting Looker outside of the dance hall, pulled her over-board by controlling an Octopus, and pulled her to her underwater base. Shortly after this, she attacked the boat with a pod of whales, and electric eels being carried by Seagulls, to subdue the guards. She was drawn into a battle with the Outsiders, and after they defeated her army, by combining their powers, and Geo-Force had freed himself from the Whale which had been ordered to eat him.
Escaping into the ocean, she was then later drawn into a battle with the rest of the Outsiders, with the exception of Metamorpho and Halo who went to rescue Looker from the Marauder's under-sea base. She was eventually defeated after besting most of the Outsiders, when Looker and Black-Lightning combined their powers, knocking her out.
Marlene was next seen while the Flash was holidaying with his girlfriend, Linda Park, on a Cruise liner. The Marauder attacked the boat with a pod of Whales and forced the crew and passengers to partake in a massive excavation on a deserted Island in the middle of the ocean. She was looking for an object known as the Crown of Enlil, and had enlisted the aid of castaways, cruiseliner prisoners and Sea-Life. At some point she had even been able to gain the control of Aquaman. After threatening the rest of the crew and passangers with death by Sharks, Flash agreed to help Marauder find the crown, and by working with Aquaman, they eventually found it.
On the surface of the Island, the Marauder was so excited by her find, she completely missed Aquaman putting it on his head and being possessed by the Babylonian God of Storms himself. After a short battle, between the Flash and Aquaman, the Island was about to be engulfed in a massive tidal wave. Being unable to save the pair at different times, Flash opted to save Aquaman, as the Marauder was too busy patting herself on the back for her victory. She was apparently killed in the wave.
Marlene’s powers allowed her to control many types of marine life, but didn't allow her to control more intelligent forms. She did display the ability to communicate telepathically with humans, at least once. Although she gained her powers through artificial means she seemed to be able to control them immediately without the need for manual controls. Her costume also displays a number of traits similar to other ocean dwellers, the ability to breath under water through a facemask, as well as increased strength and endurance to deal with the pressures of the sea, as well as the ability to fly, and shoot beams of energy from her goggles.