Musnad Abu Ya'la al-Mawsili 159:71

And with his chain of narration, he said: The Messenger of Allah (may Allah bless him and grant him peace) said: "The treasure of one of you will be, on the Day of Resurrection, a bald-headed serpent. Its owner will flee from it, and it will pursue him, saying: 'I am your treasure,' until he puts his finger into its mouth."