The numbering for "Episode 18" varies significantly depending on which Sailor Moon series or dub you are watching:
In the original 90s anime, is titled "Shingo's Love: The Grieving Doll" (Japanese: Shingo no Junjou! Kanashimi no Fransu Ningyou ). This episode shifts focus to Usagi's younger brother, Shingo, and his first experience with heartbreak and the supernatural. 📝 Episode Summary
Jumeau takes over the dolls in Mika's house to attack. Sailor Moon, with the help of Sailor Mercury and Sailor Mars, eventually defeats the monster.
This is a rare episode focusing on Usagi’s family life rather than just the Sailor Guardians' school lives.