Based on my experience, I would say it’s probably a No Knowledge Bieber In Background , which is a person who attempts to surreptitiously appear in the background of selfies, dressed in Justin Bieber garb but not actually knowing any Justin Bieber songs.

Specs for aggregating and finding content to help bring knowledge content and collaboration to nostr - Nostr Knowledge Base Improvement Possibilities. The specs are on Wikifreedia.