Beth Logan is the love interest of Martin Brundle from the 1989 horror-sci-fi film The Fly 2. She was played by Daphne Zuniga who was played by Princess Vespa in Spaceballs.
As he begins work on the Telepods, Martin befriends Bartok employee name Beth Logan. They grow closer as Martin tries to get the Telepods to function correctly.
Eventually, Beth invites Martin to a party at Bartok's specimens division. Overhearing some scientists at the party, Martin realizes that they are studying the mutated dog from two years prior.
He argues with Beth (thinking that she was aware of the dog's imprisonment), breaks away from the party, and goes down to the animal's holding pen. The deformed dog, in terrible pain, still remembers Martin, who tearfully ends its misery by euthanizing it with chloroform.
The next day, Bartok knowingly questions Martin about the dog's death, and Martin denies his involvement. Martin then reconciles with Beth, and shows her his recent success with the Telepods by teleporting a kitten without harm.
Martin and Beth become lovers, but Martin also begins showing signs of his eventual mutation into a human-fly hybrid (a fate that is still unknown to him). However, Martin does devise a potential cure for his rapid-aging condition, which involves swapping out Martin's mutant genes for healthy human genes.
Unfortunately, the Gene-swapping process would require the sacrifice of another human being, who will in turn suffer a grotesque genetic fate. Eventually, Martin learns that Bartok has hidden cameras in Martin's bungalow, and has been lying to him for his entire life.
Angrily, Martin breaks into Bartok's records room, where he learns of his father's true fate, and is confronted by Bartok. Bartok explains that he's been waiting for Martin's inevitable mutation, and that he intends to use Martin's unique condition and the Telepods' talent for genetic manipulation to amass considerable power for himself.
By this time, Martin's dormant insect genes have awakened, and his transformation into a human-insect hybrid has begun. Martin escapes from Bartok Industries, but Bartok is unable to make any use of the repaired Telepods, as Martin has installed a password and a booby-trap computer virus, which will erase the Telepods' programming if the wrong "magic word" is entered.
Bartok knows that they will never figure out the password without Martin, and so orders an extensive search for him. Martin goes to Beth and explains the situation, and the two flee.
While evading Bartok's search, Martin and Beth visit Veronica Quaife's old confidant, Stathis Borans, who is now a reclusive, embittered drunk as a result of Veronica's death.
Borans confirms for Martin that the Telepods are his only chance for a cure. Martin and Beth borrow Borans' Jeep and check into a motel, but Martin's physical and emotional changes become too much for Beth to handle, and she surrenders them both to Bartok in desperation.
Before Martin becomes fully enveloped within a cocoon, Bartok tries to get him to reveal the Telepods' password, but Martin refuses. As Martin enters the final stages of his transformation, Beth is brought to Bay 17, where Bartok interrogates her about the "magic word."
Meanwhile, the fully transformed "Martinfly" emerges from his cocoon and ruthlessly stalks and kills the scientists who manipulated him and the security guards who try to subdue him.
Despite the brutal methods he uses to eliminate the security team, a trace of Martin's former humanity remains, as demonstrated by his refusal to harm a rottweiler that is sent to sniff him out.
Bartok orders Bay 17 sealed, but Martin enters the through the ventilation system. After killing security chief Scorby and two guards, Martin grabs Bartok's hand and forces him to type in the password (revealed to be "DAD"), before dragging himself and Bartok into Telepod 1.
Martin gestures for Beth to activate the gene-swapping sequence, and, despite Bartok's protests, Beth complies. The gene-swapping sequence is initiated just as a large number of security force the doors open and storm Bay 17.
Martin is restored to a fully human form, the fly genes now removed from his body, while Bartok suffers the fate of becoming a freakish monster.
Ironically, the Bartok-beast is later placed in the same specimen pit in which he had previously kept the mutated dog, and is forced to live as a subject of scientific curiosity.
- Daphne Zuniga took the role of Beth Logan because she was attracted to the character's strength and her conviction and her emotion commitment to her relationship with Martin Brundle and his transformation into Martinfly which she becomes by a different person by the end of the movie.
- When she was interviewed about the film, Daphne Zuniga stated that Beth Logan gets stronger by what happens in the movie and changes by the end of the movie and becomes a different person. The Beth Logan character shares an almost similar character arc to Sarah Connor in The Terminator (1984). Linda Hamilton whom had played Sarah Connor was David Cronenberg's first choice to play Veronica Quaife in The Fly (1986), but Geena Davis was cast.
- Beth has sex with Martin whom although he is five years old, but due to his mutant genes inherited from his father Seth, he has the body of a young adult in his 20s. That means Beth had broken the law and had committed Statutory Rape, which it is illegal for a person to have sex with someone that is age 13 - 15 and is under the age of 18.