A number of people who own spirit vessels report having experiences that are not connected to the spirit supposedly in the vessel.
A traditional way of calling up entities is by using the Key of Solomon and calling entities in to a triangle, known as the Triangle of Art, sometimes by making a sacrifice or using blood incense whilst standing in the magic circle and then using the seal or sigil of the particular spirit/ entity that is required to appear. This spirit may direct the scryer/magician to yet another suitable spirit or agree to be bound or attached to a vessel itself. This is done by using a further seal or sigil and reciting the appropriate words of power from the key of Solomon.
The spirit often appears as a reflection in a black mirror so the process needs at least one magician/conjurer and one psychic to be present, although one person can do this if they are both a conjurer and a psychic. Conversely, a whole coven may do the conjuring.
As an exchange, the spirit connected to the vessel is promised a ‘new start’, a friendly host who will give energy to the spirit and help empower it. It is an open door for the spirit from the astral to the physical plane.
At the time of binding or attachment, many spirits agree to take on the required persona to make them appear attractive for sale. They will cast themselves as a plethora of wonderful mystical creatures or attractive people and often the spirit will be all too happy to act out the role as if they were appearing in a play or drama.
No problem there then, everybody happy.
Except when it doesn’t quite work and for example, instead of having a werewolf in a ring, you really get an incubus, or instead of a vampire you get a bad tempered and very dangerous demon, which is not bound as it is supposed to be.
I both buy and conjure spirit vessels (as you are likely aware!) and I psychically read what kind of energies are in and around haunted items and spirit vessels belonging to others. They may not be carrying quite what you expect!