Sahih Muslim 2955 b
Abu Huraira reported Allah's Messenger (ﷺ) as saying:
The earth would consume all of the son of Adam except his tailbone. From it he was created, and from it he will be recreated (on the Day of Resurrection).
وَحَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا الْمُغِيرَةُ، - يَعْنِي الْحِزَامِيَّ - عَنْ أَبِي الزِّنَادِ، عَنِ 
 الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏
"‏ كُلُّ ابْنِ آدَمَ يَأْكُلُهُ
 التُّرَابُ إِلاَّ عَجْبَ الذَّنَبِ مِنْهُ خُلِقَ وَفِيهِ يُرَكَّبُ ‏"‏ ‏.‏