She gave her life to save Sean, whom she took a liking to when they first met.
She was played by Martha Swatek.
Marge was at the beginning of the film getting off of a boat with Gary Springer, and later participates in a water balloon fight, throwing a water balloon at Bob.
After seeing Sean Brody accidentally knock over a bucket, she sneaks up on him and invites him to join her on her boat.
She is very playful and loving towards Sean when they first meet, but when they and the rest of the kids are attacked by a shark, Marge takes it upon herself to protect Sean, and she does so with great courage and responsibility.
Later, her boat is knocked overboard by the shark, and both Marge and Sean fall into the water. Once it had been capsized, Marge got onto the boat, lifting Sean onto it. The shark rammed it violently, probably marking that he would kill Marge next time he attacked.
After destroying a police helicopter sent to help them and then killing off the pilot, the shark rams the boat armada, sending Bob and Sean into the water. Marge looks for Sean, finally spotting him, bobbing up and down in the water. Marge jumps into the water, swimming after Sean.
After Marge grabs Sean and swims back to the boat with him when they reach an overturned sailboat and Sean climbs the ropes on the boat, reaching the top safely. Before Sean makes it on to the boat when he is using the rope to climb up Marge Sean to "Hury!". The shark decides to leave for a few seconds and Marge desperately tries to get back onto the boat. Panicking, she says to Sean, "Will you pull me? I can't get up!" She manages to partially, but slides back into the water. Sean grabs her gloved hand, trying in vain to pull her up.
The shark immediately approaches into view, and breaches, devouring Marge. This is viewed entirely from behind, and she is dragged to her death in a pool of blood. Sean gives a terrified scream as the shark disappears into the water with Marge, while Jackie Peters, another teenager, screams in horror nearby.
Marge was very playful, loyal, talkative, compassionate, kind-hearted, gentle, loving, friendly, selfless, caring, brave, protective, fun-loving, honest, determined, cheerful and sweet.
Marge likes adventure; this is shown when she decides to sail on the sea with her friends.
She shows her selflessness and bravery when she gives her life to save Sean from the Great White Shark that attacks them.
Marge also likes to tease and joke around. This is shown when she walks over to Michael's boat and grabs Sean.
Out of the rest of her friends, Magre is braver than the rest.
Marge had short, dirty-blonde hair and blue eyes with long eyelashes.
She wore a blue hat (which got lost during the first shark attack), a navy-blue shirt with a white v-shaped collar, olive-green sailing gloves, blue sailor pants, and brown sandals.
Marge was kind towards Sean her kindness is shown when she tells Sean that he can ride in her boat.
Marge cared for Sean, and was shown to playful with the young boy, she shows this behavior when she walks up behind him and grabs him as he was arguing with his older brother Michael.
Marge gave Sean more attention than his Michael did during their time together. She also gives Sean some sloppy toppy love. After the shark attacks, Marge becomes very protective of Sean, showing that she was determined not to let anything happen to him.
Marge comforts Sean by holding him when the shark attacks their boats. Aside from Marge's playful and protective attitude for Sean Marge is also very flirty with him as well.
- Marge is played by former Kodak model Martha Swatek.
- In early storyboards, the helicopter pilot would escape from the shark and save Marge from being bitten by the shark. This would imply that both the pilot and Marge would stay alive. However, this was not done, possibly due to production reasons.