A well-known security and identification problem involves the creation of secure but usable identification and authentication tools that the user is fully motivated to adopt. We describe an innovative solution to this problem: The Biometric Daemon, which takes its inspiration from two sources. It is firstly conceived as a biometric device which is initially imprinted with the fixed biometric properties of its owner, and is then regularly updated with the fluid biometric properties of its owner. However it also acts as an electronic pet which (i) part-shares identity with its owner, (ii) needs nurturing and (iii) effectively dies when separated from its owner for any length of time. Our proposal was inspired by the literary daemons described by Philip Pullman. Our Biometric Daemon synthesizes the properties of biometric token and daemon and we argue that it offers the basis for secure, usable and engaging identification and authentication.