Dream Manipulation is the power to affect and control dreams.
This is an ability that can vary greatly in complexity and power, with the most simple usages of it can only just alter dreams with no direct repercussions stemming from them.
However, the real, powerful users of this ability can use it in a number of ways. Some can travel through the dreams of others and use them as a medium for communication or even for attack, striking at other people in their dreams, potentially affecting them in the real world.
The greatest users of this power can completely control the world of dreams as another plane of reality, toying with it and altering dreams according to their whims, with some even being capable of dragging others into the world of dreams to kill or imprison them within its boundaries.