u/TonyGaze recommended I start a new thread with a followup question from r/AskHistorians/comments/pni4b3/did_karl_marx_arm_himself_if_so_with_what/

Reposting my question for convenience:

Could you elaborate a bit on Mensur?

I had heard of it more as something that was so removed from either combat or sport that it was basically a form of hazing in the Catholic student societies (which sounded basically like fraternities) of Bavaria and Austria. The "pledge" would stand there and as part of the initiation the existing member would cut their cheek. Then they would put a piece of horse hair into the wound which was ripped out as it was healing to accentuate the scar.

Is the above all nonsense or does it reflect some aspect of what went on in these groups?