In demonology, Crocell (also called Crokel or Procell) is the 49th spirit of the Goetia,
Once a member of the Powers, he is now a Duke of Hell who rules over 48 legions of demons.
manifesting as an angel with a tendency to speak in dark and mysterious manners.
When summoned by a conjuror, he can teach geometry and other liberal sciences. He can also warm bodies of water, create the illusion of the sound of rushing waters, and reveal the location of natural baths.
Procell is a great and a strong duke, appearing in the shape of an angell, but speaketh verie darklie of things hidden, he teacheth geometrie and all the liberall arts, he maketh great noises, and causeth the waters to rore, where are none, he warmeth waters, and distempereth bathes at certeine times, as the exorcist appointeth him, he was of the order of potestats, and hath fourtie eight legions under his power. Pseudomonarchia daemonum - Johann Wier (1583)
The Forty-ninth Spirit is Crocell, or Crokel. He appeareth in the Form of an Angel. He is a Duke Great and Strong, speaking something Mystically of Hidden Things. He teacheth the Art of Geometry and the Liberal Sciences. He, at the Command of the Exorcist, will produce Great Noises like the Rushings of many Waters, although there be none. He warmeth Waters, and discovereth Baths. He was of the Order of Potestates, or Powers, before his fall, as he declared unto the King Solomon. He governeth 48 Legions of Spirits. His Seal is this, the which wear thou as aforesaid. Goetia - S. L. MacGregor Mathers (1904)