He was a clown that they summoned to get rid of the Amazon trio. He accidentally broke Serena's dream mirror in the process. He was probably summoned by PallaPalla, but all you see of the quartet in that episode are sillhouettes.
GaraGara was a snake monster. She was summoned by VesVes. Rini jumped in GaraGara's mouth to try to keep her from swallowing Melanie's dream mirror.
ManeMane was a "copy monkey." She mimicked the Sailor Scouts' attacks, which caused Sailor Mars to discover her new "Mars Flame Sniper" attack. She was summoned by VesVes.
JaraJara was a giant plant/slot machine. Now that's a weird combination. She was summoned by CereCere, our neighborhood plant enthusiast.
A bizarre looking flying squirrel (I think) lemure. He is really fast--fast enought to burn Mars with her own attack. Summoned by JunJun. Sailor Mini-moon vaulted over his head. O_o