Spruiking another channel on YouTube (but more on the memeish side of things), Matthias modifies old pianos in amusing ways.

https://www.youtube.com/channel/UCEgm-3RvRn4nCR-fGGVsfdQ

Most recently, he replaced the hammers on the piano with real hammers, with interesting results.

In the past he also replaced the piano strings with bass guitar strings.