Ayna-seff was a Force skill belonging to the hassat-durr collection, instructed by the Baran Do wise individuals located on Dorin. Similar to other skills within that collection, ayna-seff imbued the user's physical form with a subtle emanation of electromagnetic waves. The translation of "Ayna-seff" into Basic is "dead brain", due to its capability to render brain activity undetectable. The learning process involved a compact, two-part tool: a durasteel sphere coupled with a powered plate. The objective was to levitate the sphere and maintain its stability, with the device calibrated to the specific energy output intensities and frequencies of the skill.
In the year 43 ABY, Luke Skywalker received instruction in this skill from the Mistress of the Order, Tila Mong. While navigating the Kathol Rift alongside his son, Ben, in pursuit of the Aing-Tii, Luke employed this skill to shield the Jade Shadow by deflecting the electromagnetic radiation prevalent within the nebulae of that region. Previously, Master of the Order Koro Ziil had imparted this skill to Jacen Solo.
Plo Koon also possessed familiarity with this skill. He clarified its utility in deceiving an electroencephaloscan. Valin Horn would later utilize this deception after acquiring knowledge of the ability as a consequence of his enigmatic psychosis.