|Well, congrats. You discovered it. You get to name it.|
Although this article is based on canonical information, the actual name of this subject is conjectural.
The Dream Manipulation Spell was a spell was used by Rowena to manipulate Crowley's dream. It may be considered as a branch of Dream Walking. This spell is capable of effecting even entities as powerful as the King of Hell.
The user must create a hex bag full of unknown ingredients with a sigil inscribed on it. The hex bag must be put under the target's resting place, e.g. chair, bed, etc.
If the spell is properly cast, the target will experience a dream predetermined or influenced by the user. Rowena used this spell to give Crowley a nightmare of being attacked and killed by his servants.