Qliphoth

"These be they who are Unclean and Evil, even the Distortion and Perversion of the Sephiroth; the fallen restriction of the Universe; the rays of the Coils of the Stooping Dragon. Eleven are their classes, yet Ten are they called; seven are the heads and yet an eighth head arises. Seven are the Infernal Palaces, yet do they include Ten.
In the Tree of Life, by the Waters of the River, in the Garden of Wisdom, is the serpent of the Paths; it is the Serpent of the Celestial Eden. But the Serpent of the Temptation is that of the Tree of Knowledge of Good and Evil; the antithesis and opposer of the other: the Red Coiled Stooping Dragon of the Apocalypse, the Serpent of the Terrestrial Eden.
Regard thou therefore the Celestial Serpent as of Brass, glistening with green and gold, the colours of vegetation and of growth. Banish thou therefore the evil and seek the good, thou who wouldst know the Life of Ages, thou who would follow in the footsteps of our Master, 0 Brother of the Order...
And when like our master, thou art extended on the Tree through suffering and through pain, let thy countenance be raised up towards the Light of the Holy One to invoke the Divine Brightness, not for thyself, but for those who have not yet attained unto the Pathway, even though they be thy tormentors.
But at the Fall, the Serpent of Evil arising in the Tree surrounded Malkuth, and linked her thus unto the Outer and the Qlippoth, for this is the Sin of the Fall, even the separation of the Material Plane from the Sephiroth through the interposition of the Coils of the Stooping Dragon.
Thus therefore must Malkuth be cleansed and this is the Redemption to come." - Frater D.D.C.F. (S.L. MacGregor Mathers)

from קליפות (qelippot), קליפה (qelippah)

As The Kingdom of Shells it's usually implying the 3 worlds of Edom after their destruction.

See Also:

• Dragon Rouge Tunnel Sigils
• Goetic Demons of Astrological Decans by Day and Night