Mary Jane is a short, chubby girl with black hair and bangs. Her birthday can be an event in the game. The player can give her the Deck of Cards, Bug Spray, or a MedKit/First Aid Kit. The best option is the Deck of Cards. If the player runs low on supplies and doesn't give her Water Bottles or Soup Cans, she will run away into the wasteland and become a highway woman, meaning she will be considered dead. She also loves her Tuba!
She can also become a mutant when bitten by a mutant spider, doing nothing about bugs or if the player doesn't clean the puddle of green goo with a Boy Scout Handbook or the Gas Mask . This means she will not require Water Bottles to survive, but she will require more Soup Cans as a result. The best strategy for once she becomes a Mutant is to send her out every time it prompts the player to send out a family member with nothing, and give soup to her the day that she returns before sending her out yet again. She also becomes immune to Sickness, Tiredness , Insanity, and becoming Injured. If Mary Jane mutates before you start being followed after expeditions, the bandits will take control of the area, but they will never attack the family as long as Mutant Mary Jane is the only character to ever exit the shelter.
Mary Jane is a female character with black hair like Ted. Her hair is styled in a high ponytail, held up with a pink hair tie. She has a white shirt, a navy blue skirt, white socks and brown shoes. When a mutant, she has purple skin and has rips in her clothes, and her limbs will appear unevenly proportioned in size. She will also have a giant underbite and a hump on her back.
When insane, she will pose like a chicken and stand on her seat, except from when she's Tired. Mary Jane's 3D model (appears when scavenging) shows her playing a tuba outside the shelter and she sometimes makes a tuba sound.
- Mutant Mary Jane doesn't require any water to survive so it can be very good when running low on water.
- She is one of the two items to take up 3 slots when scavenging (the other being the Suitcase).
- She is also the only item other than the suitcase to take up 3 slots when scavenging which was added in the soft release of 60 Seconds.
- When insane, she can destroy or eat the Axe, the Radio, a Can of Soup and the Flashlight, claiming the batteries from the Flashlight/Radio will give her 'energy'.
- She is the only character that can turn into a mutant.
- In a balance update, the chance for Mary Jane to become a mutant was decreased.
- She is the character that has least resistance to insanity. It is possible that it's because there's too many events that heavily damage her sanity.
- She becomes the most useful character when she is a mutant because she cannot be killed or kidnapped by the raiders or bandits during scavenging, as she always returns safely. She can also drive away bandits that attack you, being very helpful.
- If Mary Jane turns into a Mutant, on a day, there will be an event that gives you the option to talk to Mutant Mary Jane. If you do, she will run away. :,(
- Even if Mary Jane was in the shelter with other one member, that member has a chance to get Insanity, because she is not a very social character (confirmation needed).
- She is one of 3 characters that can really age in the game, the others being Timmy and Ted. Aging is shown by Timmy and Mary Jane both having birthdays, and Ted growing a beard.
- Sometimes in the journal a drawing of her playing a saxophone is seen, even though she plays the tuba. (The most frequent time this drawing can appear is in the Thunderdome events.)
- Mary Jane's face when she is a mutant resembles the popular troll face meme, however, this is not a reference, making Mutant Mary Jane look like the Troll face was completely unintentional and simply just a coincidence 
- Her name is Also another word for pot.
- She Loves soup!
- There's an event which happens if Mary Jane is not rescued: Mary Jane comes to the fallout shelter claiming that she hid inside a broken refrigerator to survive the nuke. This is a reference to Indiana Jones and the Crystal Skull where Indiana Jones hid inside a refrigerator to survive the explosion of a nuclear test.
- In Spider-Man, he has a second girlfriend named Mary Jane. It is also possible that Mary Jane's spider mutation is a Spider-Man reference, since Mary Jane mutates by being bitten by a radioactive spider.