Oh #Gezzer
You need to go find out what skin is and what you are able to do with it. Skin does not only grow on animals, it grows on bananas, oranges, potatoes etc.
'Leather' does not exist until you treat it(tanning process), then buff it up = 'leather'.
You can make leather with any skin based items, including veg, fish, cow, pig, crocodile etc; including mycelium.
As I've mentioned previously; it's not about being an echo worrier; it's about what other types of plant based materials we are able/can use to produce this finished product called 'leather'.
It's great to have all your feedback on this topic; very interesting on everyone's opinion.