Chamundikalpam is a text on sorcery or conjuration (manthravadam grantham). The text is attributed to one Shankara and is also known as Chamundi Kalpam. The text is not credited to Adi Shankaracharya but it was written by some other Shankara.
The text was widely used by sorcerers in ancient times.
The person who wrote the text was a worshipper of Raktha Chamundi. The text deals with various practices including getting rid of evil spirits, using spirits for personal gains etc.