The Living Planet (1984)

S1E15 Vanity's Mirror

A plain girl, constantly in the shadow of her prom queen sister, discovers a mystical vanity that can enchant any boy into falling for her. But there’s a dark twist: once they fall in love, she has to take their life. She eventually ensnares her sister's boyfriend, leading him to hang her with a noose. Micki and Ryan step in just in time to rescue her, but tragically, the younger sister ends up taking her own life alongside her boyfriend. The vanity disappears, though it will make a return in the second season's episode "Face of Evil."