In response to the emergence of new, paradigm-shifting technology that increases capability for the benefit and – as is the focus of this work – harm, we sought to provide contributions across three key areas. First, as a foundation, we provide a definition of the ambiguous and, at times, confusing term ‘metaverse’ and outline its unique characteristics as an emerging ecosystem. Second, we synthesise definitional framing with the violent extremist literature to offer guidance on how the metaverse can (and currently is), manifest in terrorist and extremist activities, such as recruitment, planning, finance, and malevolent creativity. We offer that while the use of the internet is not a novel application for such activities and groups, the metaverse and related technologies afford new opportunities for how the internet is used to advance violent missions and objectives. Third, we draw on psychology literature to offer potential mechanisms by which the metaverse may emerge as a future threat landscape. Future areas of research are also discussed.