(Omitting the chains of narrators) Harith Ibne Aawar says:
One Friday, Amirul Momineen (a) was delivering a sermon from the pulpit of Kufa, when a python slithered through the Elephant Gate (Baab Feel) and its head was bigger than the head of a camel and it headed to the pulpit all the while shaking its head from side to side. When people noticed the gigantic beast they moved away in terror and the python calmly came to the pulpit and whispered something into the ear of His Eminence.
The Imam responded to it in confidence. After that it returned and when it reached near the Elephant Gate (Baab Feel) it vanished from the view.
Upon witnessing this scene the believers exclaimed: This is one of the fascinating miracles of Amirul Momineen (a), while the hypocrites alleged: It is Ali’s sorcery!
Imam Ali (a) said: People, as you just saw, Messenger of Allah (s) had appointed him as his representative on the nation of Jinns, while he appointed me as his successor on the human beings. A dispute arose in his nation due to which many lives were lost and he wasn’t aware of the solution of that dispute. So he approached me in this form and asked me about its solution. One objective of coming in this form was that he wanted to make all of aware of my excellence and true station and he is more aware of my status than you all.1
1 Ath-Thaqib fil Manaqib, Pg. 248, Tr. 2.