This article seeks to propose a valuable frame for understanding which processes, either cognitive or practical, take part in the making of a terrorist act within the frame of the onlife region. A term recently coined, onlife, refers to the interacting/indistinguishable domain of online and offline world: this is the environment where today’s global terrorism/extremism flourishes. This region of complexity and the phenomena that entails can valuably explored through the General System Theory (GST). In the first part of the paper how global terrorism is changing, moving into cyber terrorism, at the light of the GST, according to recent theoretical achievements in the field is described in detail. The second part will explore a case study of onlife terrorism perpetrated in New Zealand, in order to focus the passage from the ‘possible’ idea of making a massacre to its effective performance, from onlife radicalization to the onlife event (a livestreamed attack filmed by the author) – through a deliberate use of the internet. At this point, the author will be able to come back to the question posed before, sketching some insights that might be valuable for cyber terrorism as well as for GST, especially for what concerns systemic processes within the moral domain.