When the author of the Book of Job insists upon the huge, half-witted, apparently unmeaning magnificence and might of Behemoth, the hippopotamus, he is appealing precisely to this sense of wonder provoked by the grotesque.

"Canst thou play with him as with a bird, canst thou bind him for thy maidens ?" he says in an admirable passage.

The notion of the hippopotamus as a household pet is curiously in the spirit of the humour of Browning.
But when it is clearly understood that Browning's love of the fantastic in style was a perfectly serious artistic love, when we understand that he enjoyed working in that style, as a Chinese potter might enjoy making dragons, or a mediaeval mason making devils, there yet remains something definite which must be laid to his account as a fault.

He certainly had a capacity for becoming perfectly childish in his indulgence in ingenuities that have nothing to do with poetry at all, such as puns, and rhymes, and grammatical structures that only just fit into each other like a Chinese puzzle.

Probably it was only one of the marks of his singular vitality, curiosity, and interest in details.