Hazrat Mahdi (as) will have a mole on his forehead

Abu Bashir says: Imam Muhammad Baqir (as) or Jaffar Sadik (as) said: "There are two signs of the Qaim [Hazrat Mahdi (as)]. There will be A MOLE and a mark ON THE HEAD and a mole between the shoulders.” (Sheikh Muhammad ibn Ibrahim Numani, al-Ghaybah al-Numani, p. 253)