Pierrot comes from the French word for clown, and has been borrowed for the same use in Japanese. In the Sailor Moon series, the name "Pierrot" was given to the monsters-of-the-day in the live-action series and the musicals.
|The Pierrot in PGSM|
In the live-action series, the Pierrot were a group of clown-like Youma summoned by Queen Mio to assist her efforts to recreate the Dark Kingdom in the Special Act. They fought either hand-to-hand, or with swords or mallets, and appeared to have no special powers apart from their ability to drain energy from humans. They could also perform dances and magic tricks to amuse Queen Mio or to distract their human targets.
|A Pierrot in the musicals|
They first appeared in Yume Senshi - Ai - Eien ni... and its revision, where they were loyal to Zirconia. In Shin Densetsu Kourin, another group of Pierrot appeared along with the Amazon Trio. These Pierrot were skilled in circus routines and able to fight, but were mute and seemed to have no special powers by themselves. They were more or less undistinguished, except for one smaller Pierrot who rode a unicycle.