In January 2012 a moral panic about ‘hoon cyclists’ erupted after sports celebrity Shane Warne had an altercation with a cyclist on St Kilda Road, Melbourne. Warne took to Twitter and posted an account of the event. The altercation served to focus tensions around the positioning of the cyclist in Australian automobility. The concept of ‘acute event’ is combined with a longer history of other kinds of media event, such as ‘moral panics’, to better understand events that are discursively mediated. The role of Warne in the resulting ‘cyclist hoon’ moral panic acute event is an example of the organisational role of ‘celebrity’ in participatory media. Warne’s account of cycling affectively resonates with the other car drivers as the privileged subjects of Australian automobility. This affective resonance organised the discursive field of the moral panic acute event. In this case, the techniques of social media celebrity (to produce an authentic ‘ordinariness’) also produce an affective resonance of Warne’s experience of cyclists as a driver. The folk devil figure of the ‘hoon cyclist’ challenges the hegemonic norms of car-based automobility.