Ayna-seff was a Force technique in the hassat-durr family taught by the Baran Do sages on Dorin. Like other techniques of the family, ayna-seff suffused the user's body with a low level of electromagnetic radiation. "Ayna-seff" translates into Basic as "dead brain", as it made brain activity undetectable. To learn it, a small, two-piece device was used: a durasteel sphere and a charged plate. Attuned to the precise intensities and frequencies of the technique's energy output, the goal was to raise the ball in the air and keep it steady.
In 43 ABY, Luke Skywalker was taught the technique by Mistress of the Order Tila Mong. When he and his son, Ben entered the Kathol Rift searching for the Aing-Tii, Luke would use the technique to protect the Jade Shadow by repelling the electromagnetic radiation found throughout the nebulae found there. The technique had earlier been taught to Jacen Solo by Master of the Order Koro Ziil.
Plo Koon was also familiar with the technique. He explained that it could be used to fool an electroencephaloscan. Valin Horn would do this after gaining knowledge of the ability as a result of his mysterious psychosis.