Sahih al-Bukhari 4659
Sahih al-Bukhari · Book 65: Prophetic Commentary on the Qur'an (Tafseer of the Prophet (pbuh)) · The Statement of Allah: "...And those who hoard up gold and silver (AI-Kanz—the money, the Zakãt of which has not been paid) and spend it not in the Way of Allah—announce to them a painful torment." (V.9:34)
Narrated Abu Huraira:
حَدَّثَنَا الْحَكَمُ بْنُ نَافِعٍ ، أَخْبَرَنَا شُعَيْبٌ ، حَدَّثَنَا أَبُو الزِّنَادِ ، أَنَّ عَبْدَ الرَّحْمَنِ الأَعْرَجَ ، حَدَّثَهُ أَنَّهُ، قَالَ حَدَّثَنِي أَبُو هُرَيْرَةَ ـ رضى الله عنه ـ أَنَّهُ سَمِعَ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ " يَكُونُ كَنْزُ أَحَدِكُمْ يَوْمَ الْقِيَامَةِ شُجَاعًا أَقْرَعَ " .
Allah's Messenger (ﷺ) said, "The Kanz (money, the Zakat of which is not paid) of anyone of you will appear in the form of bald-headed poisonous male snake on the Day of Resurrection."