عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا أَنَّ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَ: ((يُرْسَلُ عَلَى الْكَافِرِ حَيَّتَانِ، وَاحِدَةٌ مِنْ قِبَلِ رَأْسِهِ وَأُخْرَى مِنْ قِبَلِ رِجْلَيْهِ تَقْرُضَانِهِ قَرْضًا، كُلَّمَا فَرَغَتَا عَادَتَا إِلَى يَوْمِ الْقِيَامَةِ))
It is narrated from Sayyida Aisha (may Allah be pleased with her) that the Messenger of Allah (peace and blessings be upon him) said: Two snakes are let loose upon the disbeliever, one from the direction of his head and the other from the direction of his feet. Both keep biting him repeatedly; when they finish once, they return again. This continues until the Day of Resurrection.