Bulugh al-Maram, Book 1, Hadith 107 (English) ⓘ

Narrated Ibn Mas’ud (rad): The Prophet went out to answer the call of nature and asked me to bring three stones. I found two stones and searched for the third but could not find it. So I took a dried piece of dung and brought it to him. He took the two stones and threw away the dung and said, “This is a filthy thing”. [Reported by Al-Bukhari]

وَعَنِ ابْنِ مَسْعُودٍ ‏- رضى الله عنه ‏- قَالَ: { أَتَى اَلنَّبِيُّ ‏- صلى الله عليه وسلم ‏-اَلْغَائِطَ, فَأَمَرَنِي أَنْ آتِيَهُ بِثَلَاثَةِ أَحْجَارٍ, فَوَجَدْتُ حَجَرَيْنِ, وَلَمْ أَجِدْ ثَالِثًا.‏ فَأَتَيْتُهُ بِرَوْثَةٍ.‏ فَأَخَذَهُمَا وَأَلْقَى اَلرَّوْثَةَ, وَقَالَ: "هَذَا رِكْسٌ" } أَخْرَجَهُ اَلْبُخَارِيّ ُ (119)‏.‏ ‏2 ‏- صحيح.‏ رواه البخاري (156)‏.‏

And in the version of Ahmad and Ad-Daraqutni it is added: “Bring me more (something other than dung)”].

زَادَ أَحْمَدُ, وَاَلدَّارَقُطْنِيُّ: { ائْتِنِي بِغَيْرِهَا } (120)‏.‏ ‏3 ‏- رواه أحمد (1 /450)‏، والدارقطني (1 /55)‏ واللفظ للدارقطني، وأما لفظ أحمد، فهو: "ائتني بحجر".‏ وهي زيادة صحيحة.‏