The aim of the article is to present an analysis of the open-slot phraseme “kto [...], ten się w cyrku nie śmieje” (Who [...] doesn’t laugh in the circus). The examined phraseme is an example of a construction that has gained popularity because of computer-mediated communication and internet memes. Structural features distinguish this phraseme from other, more typical internet memes. The analysed phraseme is more similar to proverbs or other types of gnomic expressions. The quality of open slots in the phraseme is also highly distinctive because the open slots require a verbal phrase in contradistinction to other phrasemes, which usually require a noun phrase. The article includes a semantic, lexical and syntactic analysis of this phraseme, as well as an attempt to determine its origin.