Correct, it is black knot disease(fungus) and prevalent among cherry in the east. A burl that size would be worth some cash but since it's black knot not so much. Still nice to turn on the lathe though. If I lived closer I would give you $100 for it but just too far away. Good luck, someone should want it.
Looks like something from Chernobyl
Kept searching for what this is and it might be called "black knot".
Correct, it is black knot disease(fungus) and prevalent among cherry in the east. A burl that size would be worth some cash but since it's black knot not so much. Still nice to turn on the lathe though. If I lived closer I would give you $100 for it but just too far away. Good luck, someone should want it.