Despite the abundance of research into conspiracy theories, including multiple studies of Covid-19 conspiracy theories in particular, user reactions to conspiracy theories are an underexplored area of social media discourse. This study aims to fill this gap by examining a dataset of humorous responses to proliferating COVID-19 conspiracy theories based on a corpus of tweets bearing the pejorative hashtag #CovidConspiracy. We report the complex orchestration of heteroglossic discursive voices in these posts to reveal their rhetorical function, oriented towards expressing a negative stance and, in some cases, amounting to ridicule. The discursive effects of this interplay of voices entail imitation, parody, mockery and irony on the micro level, while on the interactional (macro) level, anti-conspiracy tweets jointly enact what we dub “polyvocal scorn”. It expresses multiple users’ trenchant critique and contempt for conspiracy theories, while the humour of the tweets serves to display the users’ wit and superiority over conspiracy theorists.