One can manifest physical objects through siddhi powers, but if he transcends them he can manifest God Himself.

In the dream state, all looks real. Waking up from a nightmare, we are relieved. In the same way, we should realize this existence is nothing but a lifelong dream. We should wake up and know that all is illusion. We should do sadhana realizing God as the only Truth. We will not be born again, if we have a vision of the Lord.