Satele Shan's mindscape
A mindscape was a specific Force ability that manifested as a mental environment. Those strong in the Force could utilize this ability to invade and corrupt the minds of others. An example of this is when the spirit of Tenebrae plagued the Outlander's mind following Valkorion's assassination.
Prior to the year 3627 BBY, Tenebrae once more tainted others with his influence. He trapped Jedi Master Satele Shan within the confines of her own mind, sustaining himself by consuming her mental energy. In 3626 BBY, a strike team under the command of the Eternal Alliance's Commander—previously known as the Outlander—managed to enter Shan's mind, free her from Tenebrae's grasp, and permanently eliminate him.