The counterfeit Pokémon comes in the form of Dreadheart - a cracked ghostly little teacup that you can catch in Glimwood's Tangle. It's very hard to tell the difference between a real Theffrey and a forgery, but having a real one has really changed the method of evolution. Let's see that with the full guide below.
The fake Théffroi (and Polthégeist) are more common, but they are functionally identical. The statistics are no different. These fake Pokémon may not be uncommon, but they are extremely well made. The only way to tell the difference is when the Pokémon are in dynamax form. There is a clue that you can find in the oversized versions.
How To Get An Authentic Polthegeist | Fake Pokémon Guide
Théffroi and Polthégeist can be fakes - and finding an authentic cup of tea is tricky. The only way to tell the difference is to look for an authenticity sticker on the underside of Polthégeist when it changes to Dynamax form - or by looking carefully in the summary page. Otherwise, there is no difference between the fake version and the genuine version.
The ghostly Théffroi teacup appears in Glimwood Tangle - and rarely during Max Raid battles in nature. Rarely, the Pokémon you can catch will be genuine - like, very rarely. A 'real' Théffroi only appears 1% of the time. It's a great pain in the buttocks. If you catch one, you can check out the normal Pokémon summary page.
To evolve Thrift in Polthégeist. In Stow-on-side, you can talk to an NPC who will give you Object of Théffroi's evolution. To make Théffroi a polteageist, you will need the Cracked pot or Chopped pot. The Cracked Pot is used to evolve tampering, while the rare Chipped Pot is for true poltesists - the Cracked pot is sold by the Stow-on-Side Rare Item Dealer. So you will need to check daily if you have any additional items.
You can also find a Cracked pot place one of the ladders on Stow-on-Side for free. If you want to try to evolve, take the one on the roof in the northeast corner of town.
