Musnad Ahmad 30:3214

Muhammad ibn Ja‘far narrated to us, he said: Sa‘id narrated to us, from Qatadah, from al-Hasan, from Abu Hurayrah, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Whoever leaves behind a treasure, it will be represented to him on the Day of Resurrection as a bald-headed serpent with two black spots, following him. It will continue to pursue him, and he will say: 'Woe to you! What are you?' He said: It will say: 'I am your treasure which you left behind after you.' He said: Then it will put its hand into its mouth and gnaw it, then it will follow the rest of his body."