What's the rarest show you've seen?

Could be a band that plays shows infrequently, doesn't come to your country often, they didn't exist as a band for very long, played a rare song or set, or something like that.

Mine is probably Sleepwave, on the Norma Jean O'God 10 year tour (with The Ongoing Concept and '68, dope lineup). Still my favorite music Spencer has done haha. Runners up would be Ocean Grove opening for ABR (still their only USA shows so far, and when they only had banger records in their catalog), Rival Choir and Attalus.