The numbering for "Episode 18" varies significantly depending on which Sailor Moon series or dub you are watching:
Queen Beryl briefly appears to reprimand Nephrite for his slow progress, while Zoisite mockingly watches from the sidelines. Sailor Moon Episode 18
The Youma Jumeau is a "monster-of-the-week" themed after a French porcelain doll. 📺 Versions Across the Franchise Sailor Moon Episode 18