Dissception

Dissception (noun):

A portmanteau of "dis," slang for disrespect, and "Inception," a reference to the complex layers of reality in the eponymous movie.

A situation or act in which an individual attempts to disrespect or belittle another, but inadvertently ends up disrespecting or belittling themselves, often in a manner that is not immediately apparent.

His attempt to mock her fashion sense was a clear case of dissception when everyone pointed out his own outdated style.