Ugly Man

"Ugly Man" was a monster from Buffy the Vampire Slayer and was based on the traumatic memory of the Kiddy League Coach from his young victim - who was beaten into a coma yet somehow manifested powerful psychic powers that altered reality itself.

"Ugly Man" was a brutish thug that inspired great fear in his young victim and it was not until Buffy finally convinced the boy to face the monster that he was able to awaken from the coma: suggesting that his fear of the "Ugly Man" was also acting as his prison, trapping him inside a living nightmare.

Due to the "Ugly Man" only existing in dreams it is safe to assume the monster is now gone for good, especially since the Kiddy League Coach has been captured and (presumably) punished for his crimes.