Poltchageist looks like a regional form of Sinistea, but it was recently discovered that the two Pokémon are entirely unrelated.
Poltchageist is a Grass/Ghost-type Pokémon. It takes double damage from Fire, Ice, Flying, Ghost and Dark, resists Water, Electric, Grass and Ground, and is immune to Normal and Fighting. Its base stats add up to 308: the highest is Special Attack (74) and the lowest is HP (40).
It is the first stage of its evolution line, along with Sinistcha. Its ability is Hospitality, and its Hidden Ability is Heatproof. It is in the Mineral and Amorphous egg groups and, being genderless, can only breed with Ditto. In Scarlet and Violet it learns 13 moves by level-up and 30 by TM.
BASE STATS
ABILITIES
When the Pokémon enters a battle, it showers its ally with hospitality, restoring a small amount of the ally's HP
The Pokémon's heatproof body halves the damage taken from Fire-type moves.