We examined the ethical implications of a mythical online student with a carefully concealed real identity who took part in an online post-graduate course. The mythical online student took part in all student activities and provided co-students with cognitive and technical support as a covert second facilitator; consequently, students found scaffolding unobtrusive and integrated the unknown virtual student into the learning community. We explored the ethical implication of undisclosed identity and analyzed Students' reaction to the disclosure of the mythical student after the course. The study confirmed our success in creating a convincing virtual student, but this success precipitated some shock, disbelief, and dismay. Most students accepted the presence of a virtual student, but some felt betrayed because her real identity was hidden. Recommendations for implementing such a virtual tool ethically are advanced, along with suggestions for teaching situations that may benefit from its use.