One of the more mysterious psionic powers is Collapse Time. As written in The Illithiad:
Collapse time allows an illithid to crystallize time from the continuum, forming a dollop of thick, gooey material called quintessence. Quintessence shimmers like a silver mirror from some angles, but is transparent form others; it brings a cool numbness that slowly fades after contact with the skin.
Time Particle is the more formal name of Quintessence. This substance is used to put an object in stasis. The largest us of this stuff is in the thousands of Hibernation Bay lining the interiors of the Helas Vessels.