Is the birth of a mule one of the signs of the Hour?

It is incorrect that the emergence of a "mule" is among the signs of the Hour. Rather, it is the emergence of a "beast" (dābbah) from the earth, as stated in the Qur'an and the Prophetic Sunnah, and that it will speak to people. It will emerge when people become corrupt and change their religion.

Noble hadiths have mentioned that the emergence of the beast is among the major signs of the Hour, after which faith will be of no benefit to those who had not believed before.

No marfūʿ hadith( attributed to the Islamic prophet Muhammad ) has been reported regarding the shape of the beast. However, narrations from the early Muslims have been reported from the Salaf describing it with different characteristics, and mentioning that it will distinguish the believer from the disbeliever.