The paper zooms in on the myth evolution in advertising discourse and its semiotic and cognitive functions. Myth is an instrument to advance and mediate knowledge blended with rationality, emotionality, and pragmatic purposes. This article aims to present the development of King Arthur’s sword Excalibur as a source for mental and technological construal in modern advertising discourse, where the mythological and technological meet to encode new conceptual projections referring to the outer world. Outlining the core conceptual characteristics of EXCALIBUR as a weapon and two dynamic frames, we are able to outline the references to the secondary conceptualizations interwoven with interpretations of the concept. We demonstrate that EXCALIBUR can be interpreted in two mutually exclusive ways of its source that shapes the construal of the mythological Blended space 1 to which technological sphere is added in the Mental space 2, which can specifically focus our attention on certain conceptual characteristics projected in discourse. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.