She's a bully and a sadist who takes pleasure in killing people in hit and runs and in making life miserable for the movie's protagonist Melvin.
A scantily clad villainess, Wanda's preferred outfits are bikinis and minidresses with high heeled pumps. She's often wearing her high heels when she works out in the gym, going to the sauna or even having sex!
Wanda along with her friends Julie, Slug and Bozo are frequently seen working out at the same gym that Melvin works at as a janitor. They dislike him and delight in bullying him.
Early on in the movie Wanda is talking to her boyfriend Slug about the hit and run murders they commit, talking about it starts to turn her on and they have sex there and then. Melvin walks in on them and Wanda threatens to kill him with a knife.
Later that evening Wanda and her friends commit another hit and run. Their victim is a child riding a bicycle. This thrills Wanda and she and Julie get out of the car and take photos of their deceased victim.
The next day she and her friends come up with a plan to publicly humiliate Melvin. The end result is Melvin ending up kissing a sheep in front of everyone at the gym. Wanda enjoys his humiliation as does everyone else. Melvin, totally embarrassed, flees from those taunting him. He manages to escape through an upstairs window but lands in a barrel of chemical waste in a truck outside. Wanda, along with everyone else, makes her way outside onto the street to see what happened. She laughs at the sight of Melvin on the ground and takes great pleasure in watching him writhe around in agony as the chemicals burn him.
In the gym sometime after the incident she and Julie look at the photos they took of the dead boy on the bicycle they ran over. She tells Julie that the sight of the blood turns her on.
Later in the gym's sauna room she takes out the photos she took of the boy and masturbates to them. She's too busy enjoying herself to notice Melvin (now The Toxic Avenger), who comes into the sauna room and gains a measure of revenge by picking Wanda up and setting her bare ass down on the hot rocks. She screams in agony as Toxie holds her down on the hot rocks, her flesh sizzling.
This is where she is last seen in most cuts of the movie, but in certain cuts/deleted scenes she is seen in a police station having been arrested for the hit and run murders. She is wearing a kind of diaper on her ass from where she was burnt by The Toxic Avenger, and is struggling to walk properly and likely feeling a little humiliated.