[Machine] The Messenger of Allah ﷺ was asked about a person who sees semen in his dream but does not remember having a wet dream. He replied, "He should perform ghusl (ritual bath) even if he thinks he had a wet dream but did not see any semen."  

سُئِلَ رَسُولُ اللهِ ﷺ عَنِ الرَّجُلِ يَرَى فِي الْمَنَامِ الْبَلَلَ وَلَا يَذْكُرُ احْتِلَامًا؟ قَالَ يَغْتَسِلُ وَإِنْ رَأَى أَنَّهُ احْتَلَمَ وَلَمْ يَرَ بَلَلًا فَلَا غُسَلَ عَلَيْهِ