@DAiDEViL i have a part-time job at a university, and with some colleagues, we are working on the r&d infrastructure of the institution. from time to time, that involves checking old inventories and stumbling upon shit nobody touched since forever. usually these useless old assets get disposed of asap. we often find things like broken spectrometers, microscopes, old laboratory supplies, and some crazy stuff too.
and this is the way how i got a pentacon 200mm f4 m42 this afternoon

it looks a bit worn, but aperture ring is smooth, focus isn't bad either. there's some dust in it, but no fungus fortunately. too bad i didn't bring the m42 adapter, so i'll have to wait until tomorrow night when i get home. can't wait to try it out.