The Phony Form (if it lacks a mark of authenticity) requires a Cracked Pot to evolve.
The Antique Form (if it has a mark of authenticity) requires a Chipped Pot to evolve.
Polteageist is a rotund purple ghost that lives in a teapot. It is made of black tea that tastes very good, but can cause indigestion or stomach aches if drunk in excess. Only its trainer is allowed to drink the tea. They live in hotels and restaurants to infect teapots to create more of their own kind. As such, Polteageist is a genderless species.
Most of the teapots that Polteageist infects are forgeries, but occasionally an authentic one is found (with a mark of authenticity on the bottom). Polteageist attacks by shooting tea at its enemy's mouth; causing them strong chills when swallowed.
Polteageist may be based on a teapot and black tea. It may also be inspired by the idea of a genie, which are often depicted as residing in oil lamps. Its forms may be based on Teapot forgeries being done in Britain.
Polteageist may be a combination of poltergeist (ghost that moves objects/makes noises) and tea.
Potdeath may also be a combination of pot and death. It literally means "it's a teapot" (potto desu).