Vaisampayana said, “Witnessing that dreadful and wonderful body of Hanuman, like unto the Vindhya mountain, the son of the wind-god became bewildered. Then with his down standing erect, the noble-minded Bhima, joining his hands, replied unto Hanuman saying (there), ‘O lord, by me have been beheld the vast dimensions of thy body. Do thou (now), O highly powerful one, decrease thyself by thy own power.

In plain words: Bhima, son of the wind god, is confused and overwhelmed by Hanuman's enormous body. With folded hands he says he has seen it, and asks Hanuman to make himself small again.