Which once great teenage girl character endured the worst case (https://tvtropes.org/pmwiki/pmwiki.php/Main/CharacterDerailment) of "character assassination" (https://web.archive.org/web/20140401071852/http://forums.televisionwithoutpity.com/topic/3127454-7th-heaven-there-is-no-god/page-315#entry15270886).

Before Lisa Bonet appeared in the film Angel Heart, which included nudity and a sex scene, Denise (https://tvtropes.org/pmwiki/pmwiki.php/Characters/TheCosbyShow) was a cool, laid-back, and outspoken girl. But after Angel Heart, Denise's character became (https://www.lipstickalley.com/threads/things-you-didnt-like-about-the-cosby-show.1418287/post-34918626) braindead and flighty (https://www.lipstickalley.com/threads/the-cosby-show-why-was-bill-and-clair-so-mad-at-denise-for-marrying-martin.4811928/post-79469300). Even worse, she was now (https://web.archive.org/web/20140401071852/http://forums.televisionwithoutpity.com/topic/3127454-7th-heaven-there-is-no-god/page-315#entry15273185) also a stepmother to little Raven-Symone, who stole the spotlight.

Meanwhile, Mary (https://tvtropes.org/pmwiki/pmwiki.php/Characters/SeventhHeaven) on 7th Heaven, started off as being a mature and responsible teen who sometimes rebelled but ended up doing the right thing. But after Jessica Biel posed (https://web.archive.org/web/20140401071852/http://forums.televisionwithoutpity.com/topic/3127454-7th-heaven-there-is-no-god/page-315#entry15273390) provocatively for a men's magazine, her character devolved (https://www.datalounge.com/thread/30616895-tina-yothers-ruined-family-ties-) into being a dysfunctional, selfish mess, who got dishonorably written off due to being kicked out of her home to live with relatives because of her bad behavior. And when even when Mary comes back, she's now an airhead who can't get things right.