From Cyprus Police:
The Office for Combating Electronic Crime has received multiple complaints from citizens about the phenomenon of "challenge games" aimed at causing mainly underage users to take various actions that could harm themselves. Specifically, various users of social networking users accept "challenge" messages and invite them to follow specific instructions in order to pique their interest but at the same time may find themselves in undesirable situations. The Office for Combating Cybercrime advises the public to immediately exclude senders of these messages and to have no contact with them. Cyberalert.cy