Abu Dharr said (and not the Prophet): If there is not anything like the back of a saddle in front of a man who is praying, then a donkey, a black dog, and a woman cut off his prayer. I asked him: Why has the black dog been specified, distinguishing it from a red, a yellow and a white dog? He replied: My nephew, I also asked the Messenger of Allah ﷺ the same question as you asked me. He said: The black dog is a devil. (Using translation from Abū Dāʾūd 702)
قَالَ رَسُولُ اللهِ ﷺ يَقْطَعُ صَلَاةَ الرَّجُلِ إِذَا لَمْ يَكُنْ بَيْنَ يَدَيْهِ كَآخِرَةِ الرَّحْلِ الْمَرْأَةُ وَالْحِمَارُ وَالْكَلْبُ الْأَسْوَدُ قُلْتُ مَا بَالُ الْأَسْوَدِ مِنَ الْأَحْمَرِ؟ قَالَ ابْنَ أَخِي سَأَلْتُ رَسُولَ اللهِ ﷺ كَمَا سَأَلْتَنِي فَقَالَ الْكَلْبُ الْأَسْوَدُ شَيْطَانٌ