本身法相 He Took His Own True Form
好大聖，即轉身跳入裡面，不施變化，就將本身法相。真個是：好大圣，即转身跳入里面，不施变化，就将本身法相。真个是：
逐句解 Line by line
The fine Great Sage turned about and sprang inside, and this time he worked no transformation at all but went in his own true form.
不施變化 — he applied no changes. He has entered this cave twice already, once as a fly and once by being swallowed; the third descent is made as himself, which is why the poem that follows can afford to be a portrait. 相 is xiàng here, an appearance or a form, not the xiāng of doing something to each other, which the battle verse used a few passages back.
It was truly a case of this:
The formula that introduces verse, and here it introduces the only extended description of Pilgrim's own body in the chapter.
Odd-shaped, with jutting cheeks, and hard of heart within; a monster from his youth, and stout in supernatural strength.
別腮 is the strange set of his jaw — the simian face the novel never lets you forget. 為 is wéi, to be or to act as, not the wèi that means for the sake of. The line is his own CV, and it opens with the word monster without embarrassment.
High and low, his face outdoes a saddle-bow; his eyes shoot golden light, bright as fire.
馬鞍鞽 is the raised bow of a saddle, and comparing a face to one is not flattering: it means the brow and jaw stand out and the middle is sunken. 鞽 is a rare character even for the Ming — a piece of tack vocabulary that has not survived into common use.
The hair all over him is stiff as steel needles; the tiger-skin kilt is tied on and its bright flowers rustle.
虎皮裙 is the tiger-skin kilt he has worn since the very first chapters, and it is worth remembering that it is not a costume but a trophy — he killed the tiger and put it on. 繫 is xì, to tie or fasten.
The third descent is made undisguised, and the novel marks the change by giving him a body. For two chapters he has been a fly, a swallowed lump, a voice in somebody's stomach; here he is a shape with cheekbones and hair and a kilt.
The portrait is unsentimental to the point of rudeness. He is odd-shaped, saddle-faced, bristly, and the poem says so in the tone of an admiring description, which is exactly how the novel has always regarded him.