The evil Heather Flynn
Heather Flynn (Kathy Trageser) is the main villainess from "Indecent Proposal," episode 4.20 of Step by Step (airdate March 31, 1995). She is a high school ethics teacher, whose students include JT Lambert and Dana Foster.
The episode's early scenes showed Heather teaching her class before dismissing her students and handing their assignments back to them, with Heather revealing that one of them received an A+. Dana assumed that she received the high grade, but in actuality, JT was given the A+, with the reveal coming as Heather handed JT his assignment and commented that he was becoming her favorite student. Dana expressed shock regarding JT's high grade, and stormed back into the classroom to confront Heather, only to overhear her teacher in a phone conversation.
To Dana's surprise, Heather turned heel by revealing her plans to sleep with JT, adding that she gave JT the high grade as part of her plan to seduce him. Upon hearing Heather's villainous plan and revelation, Dana informed JT, who responded with disbelief and assumptions that Dana was jealous of his high grade. At that moment, JT received a phone call from Heather, who invited him over to her place for nightly tutoring, proving Dana's claims to be true. However, JT cheered over the fact that he was likely going to hook up with his teacher, and as planned, he went to Heather's home, where the villainess set up her planned night of seduction.
As the night progressed, the evil Heather revealed her true motivations for inviting JT to her place, and increased her seduction towards her student by making out with him repeatedly. JT became more and more apprehensive and nervous with each advance, as he wanted to get to know Heather first, but eventually, he stood up and informed the villainous professor that he couldn't go through with a sexual tryst with her. Heather's fate wasn't revealed after JT left her place.