Khecarī

Khecari (खेचरि):—The concept of khecara (etheric state of meditation) becomes concretized on an alchemical level as well.

Mercury (rasa), when bound, is said to become khecari, possessed of the power of flight, a power it transmits to the alchemist who holds a capsule of said mercury in his mouth. If, however, it is heated before it has been properly prepared, or too rapidly, it can be lost to evaporation.

Here, it is said that until its wings have been clipped (pakṣa-ccheda) through various stabilizing techniques, unrefined mercury becomes subject to flight, i.e., evaporation (pātana), and may be “gone like a goose” (haṃsaga).

Here, mercury behaves like the haṃsa of the vital breaths: unless these are tethered by yogic discipline, the breath will eventually fly up out of the body to be lost forever, and the person will die.

1) Khecarī (खेचरी):—The Sanskrit name for the goddess representing the fourth secondory gross element “wind”, according to the Ṣaṭsāhasra-saṃhitā.

2) Khecarī (खेचरी):—First of the eight Mahāmātṛs existing within the Mātṛcakra, according to the Kubjikāmatatantra.

Khecarī stands for “ether” and her name literally means “she who moves through the sky”.

The eight Mahāmātṛs are also called mudrās because all the directions are ‘sealed’ by them.

Khecarī (as do each of the eight Mahāmātṛs) divides herself into eight (secondary) mātṛs, presided over by a Bhairava (fearsome manifestations of Śiva) and his Mātṛkā as consorts.

The Mātṛs of this first and north-eastern group are born from Khecarī’s body and represent the eight directions of the compass from east to north-east.

The eight deities originating from Khecarī are called:

    Aindrāṇī,
    Agnimātarā,
    Yāmyamātrī,
    Rākṣasī,
    Vāruṇī,
    Vāyavī,
    Kuberā and
    Īśānī.

Sometimes, this first group of eight Mātṛs are represented by the eight Mahāmātṛs themselves (see Ṣaṭsāhasra-saṃhitā 23.19cd-21).

Source

http://www.wisdomlib.org/definition/khecar%C4%AB/index.html