Marcy Fleach, better known as "Hot Dog Water", because she smells of hot dog water, is a friend and former rival of Velma Dinkley .
She has competed in some Science Fairs along with Velma, and loses them all.
She went to China. (The Dragon's Secret)
She attacked people at Creepy Spooky Terror Land in the guise of the Manticore, in order to be rich. (Menace of the Manticore).
She brefriended Velma and worked for Mr. E, and become a replacement for Daphne. (House of the Nightmare Witch)
She then tried to steal the Planispheric Disk by dressing up as Dark Lilith. Velma only knew Dark Liltith's true identity. (Night on Haunted Mountain)
Mystery Inc. hired her to steal the original Mystery Inc.'s pieces of the planispheric disk. (Wrath of the Krampus)
She was killed by the Kriegstaffebots. (Through the Curtain)
She was alive in the new universe. (Come Undone)
17: Where Walks Aphrodite
18: The Dragon's Secret
21: Menace of the Manticore
28: House of the Nightmare Witch
29: The Night the Clown Cried II-Tears of Doom!
30: Web of the Dreamweaver
31: The Hodag of Horror (episode)
34: Night on Haunted Mountain
39: Wrath of the Krampus
51: Through the Curtain
52: Come Undone