[s7e19] The One With Ross And Monica's Cousin -

Originally stays at Monica and Chandler’s, but Chandler cannot stop staring at her, forcing her to move to Ross’s apartment.

Despite being her cousin, Ross becomes convinced she is seducing him after they share wine and watch Logan's Run . He makes a disastrous move to kiss her, leading to a long, painful silence and her immediate departure.

Rachel and Phoebe realise they have completely forgotten to plan Monica’s bridal shower.

imdb.com/name/nm0000579/">Matthew Perry's brief appearance in this episode or other Season 7 highlights? The One with Ross and Monica's Cousin - IMDb

Ross and Monica’s cousin, (guest star Denise Richards ), comes to stay for a few days. Her presence creates awkward tension as her beauty "mesmerizes" everyone she meets:

When Monica finally arrives, she insults the guests—thinking they have already left—only for them to jump out for a surprise reveal, creating a highly uncomfortable moment.