"Euphoria" opened its latest season with a wild storyline for Sydney Sweeney's character, Cassie ... and Sophie Rain told us it left her none too pleased.

The content creator was apparently just as taken aback as the rest of the internet seemed to be at seeing Cassie dressed in a dog outfit and doing pooch activities for money as an adult content creator.

Sophie told us she thinks it's cool the show is featuring what's clearly supposed to be OnlyFans ... but in her opinion, the show is doing it all wrong.

According to Sophie, she would never degrade herself to that extent on the website, and not only that ... she doesn't know any top creator who would.

She said, "They're definitely just making it dramatic for entertainment, but it's not reality."

Remember ... the storyline actually made headlines before the season even premiered, with Cassie being featured in a promo dressed like an infant. Sophie had even stronger views on that outfit, saying, "That should almost be illegal."

Watch the video to hear why Sophie finds the distasteful portrayal so damaging.