This cute little entity is also know as the awizza of Sinti folklore.
It basically can be identified trough the Search Out Ritual ,where it will be seen as a dark-greenish(?) glowing lump sticking out of the hosts body near the head or chest. The hosts head will be twisted and non-euclidean to a degree based of the time the Awizza had time to spread. It is a kind of parasite feeding from death in close proximity ,impatient enough to flood his hosts mind with pictures and emotions of madness in an attempt to commit suicide or kill another person. The Awizza is somehow bound to a special location ,leaving its host when taken away from there.
I also have to mention that they are minor entities with little power ,therefore mostly attaching to weaker and open minds like children ,mental cases and that stuff. If not properly Dispersed however they tend to mutate ,suddenly clinging to victims they would never had touched before like pets or supposedly even plants!
To banish it you might first read into the 'Snap out of Possesion' Part of the Rituals. This should bring the Awizza out of the hosts body. If you are very lucky the Awizza will be in a state where he didn't find a good host for some time and is therefore already 'incorporeal' floating around his turf.
Second and third Steps are 'Tie to Object' and 'Disperse'. Be extra careful with the last one because these bggers are persistent as paradise lost.