While both brand advocacy and protest have long been theorised as key facets in consumers' behaviour, we submit that in the participatory culture of social media, where consumers are free to create and publish their own content, the mischievous play has also become an inevitable form of online culture that brands must deal with.Drawing from Caillois' sociology of play and the cultural power model, we explore how consumers may playfully hijack brands' User-Generated-Content (UGC) hashtag campaigns. Based on a non-participatory netnography, we observed consumers' tweets to unpack their playfulness in responding to brands' marketing communication messages on Twitter and then theorised how consumers use mischief as a form of resistance against marketing practice rather than brands themselves.