Summon Poltergeist is a conjuration effect from Witchery. When performed, after about 30 seconds, a Poltergeist will be spawned. The spawned Poltergeist will be controlled by the user.
It can be performed by using a Wormwood, Refined Evil, and Focused Will on a Brazier, then lighting it with a Flint and Steel. The Brazier must have Altar power.