Then, as a cloud in rain-time grows His form, dilating, swelled and rose. Wide as the space from heaven to hell Her jaws she opened with a yell, And rushed upon her fancied prey With cloud-like roar to seize and slay.

In plain words: Hanuman makes his body grow huge, like a rain cloud. The demoness opens her jaws enormously wide and rushes at him with a roar to eat him.