There are different types of Feeders both on the astral & spiritual planes. No specific event brings them on, and they are roaming entities that feed on hosts, typically animals or humans. They are not beings that can be bound as spirits are bound, nor would anyone want to, as a contained Feeder is a dangerous situation for anyone in the dwelling/location.
Feeders are said to be rare, as they aren’t plentiful, but appearances do happen, and being a Spirit Keeper or practicing magic doesn’t make you any more or less susceptible to being chosen as a host.
Feeders were said to prey on people whom they think they can gorge on energy from. They start slowly, picking at energy bit by bit. And as that person’s energy becomes more drained, they do things to try and provoke more energy from you, like fear, stress, anxiety, etc. They are highly evolved beings that can shape-shift not only themselves but also an extension of their core energy to be multiple things, which is what happened here.
Stories have held that Feeders might be more prone to target young kids, as they are easily provoked and have a lot of energy. Feeders typically stay with a host anywhere from a few days to a few weeks before they move on. They don’t stay in one place for long or with one host for long, and they don’t typically move from one family member to another. They roam constantly and feed from multiple sources because each of our energies is different, and they do best feeding on variety rather than from a single energy imprint.