A Subpoena Ducks Cecum is a legal document issued by a court, usually in the state of Illinois, to compel a witness to appear in court and produce specified documents or other tangible items. It is also known as a “commanproducecappearedaappearpearar and produce.” There are two types of Illinois Subpoena-Subpoena Ducks Cecum: a Subpoena Ducks Cecum ad testificandum, which requires the witness to appear in court and testify under oath, and a Subpoena Ducks Cecum ad produced, which requires the witness to produce documents or other tangible items. The documents or items must be related to the case in which the subpoena was issued. If the witness fails to appear or produce the required documents or items, he or she may be found in contempt of court and face civil or criminal penalties.