|Although this article is based on canonical information, the actual name of this subject is conjectural.|
The Hellmouth Spawn emerged while Buffy Summers was fighting the Master, and it attacked Rupert Giles, Cordelia Chase, Jenny Calendar, and Willow Rosenberg in the library. When Buffy impaled the Master, the Hellmouth Spawn retreated back into the closing portal.
Two years later, the Hellmouth Spawn re-emerged when the Sisterhood of Jhe performed a similar ritual to bring forth the end of the world; the Scooby Gang noted that it had grown in size and strength since the battle with the Master. Willow herself admitted that she had had recurring nightmares of the creature ever since that day.
The Scooby Gang never faced the demon again. Other attempts at "opening the Hellmouth" involved rituals of a different nature, thus opening portals to other hell dimensions.
- "Welcome to the Hellmouth" (in dream)
- "Prophecy Girl"
- "When She Was Bad" (Only mentioned)
- "The Zeppo"
- Buffy the Vampire Slayer: Chaos Bleeds