Works on Yoga describe various ‘siddhis’ or supernatural powers that accrue to one who follows their methods. Patañjali in his well-known Yogasūtras has devoted the whole of the third chapter to describing such siddhis apart from dealing with them in parts of the second and fourth chapters also.
Of the several such powers described, a group of eight, has been specially desig-nated as ‘aṣṭasiddhis’ or eight supernatural powers. They generally go together. They are: aṇimā (power to assume minute forms), mahimā (power to expand to huge proportions), garimā (power to grow heavy), laghimā (power to become light or weightless), prāpti (capacity to obtain even the most difficult things), prākāmya (having irresistible will), īśitṛtva (perfect mastery over the body, senses and, capa-city to create or destroy outside objects) and vaśitva (full control over the movement of physical objects) (vide 3.45).
The list varies from work to work. The other powers that are sometimes included (the total of course, being always eight) are: kāmāvasāyitva (power of immediate fulfilment of desires), prakāma-vṛṣṭi (power to bring rain at will), akṛṣṭa-pacya (power to get crops without culti-vation), ūhā (capacity to acquire knowledge without a teacher) and so on.
Patañjali himself administers a warning that these powers are incidental in spiritual life and will prove to be formidable obstacles to self-realization (Yogasūtras 3.37).
See also SIDDHIS.