I remember when I was with the Messenger of Allah ﷺ and I tied a rock to my stomach because of hunger, and now my zakah is forty thousand. It was narrated from ʿAli ؓ ... and he mentioned the same hadeeth, and said in it. The zakah of my wealth is forty thousand dinars. (Using translation from Aḥmad 1367)
لَقَدْ رَأَيْتُنِي مَعَ رَسُولِ اللَّهِ ﷺ وَإِنِّي لَأَرْبِطُ الْحَجَرَ عَلَى بَطْنِي مِنَ الْجُوعِ وَإِنَّ صَدَقَتِي الْيَوْمَ لَأَرْبَعُونَ أَلْفًا