Ganesha had manifested in the form DhumravarnaDhumravarna
Ganesha had manifested in the form Dhumravarna... that literally means smokeless form. Smoke here depicts the transition between the unreal manifestation that can be perceived by real eyes (Sagun) and the real manifestation that cannot be perceived by real eyes (Nirgun). He gave a message to his devotees that they strive to move from the unreal world of miseries in the real world of Divinism.
Dhumravarna manifested to give the message to his devotees that they can attain the salvation when they don’t have the EGO.
One interesting Hindu Mythological legend is there related to the birth of Dhumravarna.
Long time ago, once BrahmaBrahma
According to Hinduism, the whole creation is the work of Trimurti (the Hindu Trinity)... was thanking the Sun that he was responsible for the worldly activities that were happening around the world. After this incident sun became arrogant that the three worlds are governed by him. He considered himself to be the wholly solely in charge of the three worlds.
It is believed that when the thought of the ego passed in the mind of the sun, he sneezed and gave rise to a boy with demonic cult. The boy went down to the world of demon and there he met Sukracharya, the great preceptor of Demons. He christened him with the name “Aham" that literally means Ego. Sukracharya gave this name to the boy as he was born from the ego of the Sun.
Sukracharya advised Ahem to worship Dhumravarna. After many years of severe penance Dhumravarna appeared before him and gave him the boon that he would succeed in conquering all the three worlds. Rejuvenated with the boon Ahem conquered the three worlds.
Once Aham saw Mamata, daughter of Pramadasura. He got mesmerized with the beauty of Mamta that he decided to marry her. Later the couple was blessed with two sons Garva and Sreshta. Here Garva and Sreshta are the synonym of EGO.
Meanwhile, the Gods became sick of the demonic rule of Ahem. They prayed to Dhumravarna for the solution. Dhumravarna descended to their rescue and subdued the demon Aham.