Alone he leapt down the mountain, and there beside the road, with a shake of his body, transformed himself into an aged Daoist.

搖身一變 (yáo shēn yí biàn), "one shake of the body and he was something else," is the standard formula for shape-shifting, used of immortals and demons alike -- and it is Monkey's own signature phrase, which the chapter will hand back to him later. 道者 (dào zhě) is a Daoist, a man of the Way. The costume is chosen with care: nothing disarms a compassionate monk like another religious.

And how, in truth, was he got up? Behold:

怎生打扮 (zěn shēng dǎ bàn), "got up how, exactly?" -- a storyteller's cue, the verbal equivalent of a drumroll. 但見 (dàn jiàn), "one saw only," is what ushers in the set-piece verse that follows.

A star-crown gleaming bright, crane-white hair loose and tangled;

星冠 (xīng guān) is the star-cap, the ritual headdress of a Daoist priest; 冠 as a noun is guān. 鶴髮 (hè fà) is "crane hair," white as a crane's feathers -- the standard sign of venerable age.

a feather robe girt with an embroidered sash, cloud-shoes trimmed in yellow palm-fiber;

羽衣 (yǔ yī), the feather robe of a transcendent, and 雲履 (yún lǚ), cloud-shoes. Every item is genuine Daoist kit. Holiness is the bait, and the holier the costume the better it works.

spirit clear and eyes bright as an immortal guest's, frame hale and body light as the Star of Longevity.

仙客 (xiān kè) is a visiting immortal; 壽翁 (shòu wēng) is the Old Man of Longevity, better known as 壽星, the god of long life -- the domed-forehead figure still handed round at birthdays on cakes and embroidery.

Say nothing of the Green-Ox Daoist — he outshone even the Master of the Plain Contract.

說甚麼 (shuō shén me), "never mind, say nothing of," with 甚 as the question-word shén. The couplet then measures the disguise against two famous adepts. 清牛道士 is the edition's spelling of 青牛道士, the Green-Ox Daoist -- the sobriquet of Fēng Jūndá, who in Ge Hong's 神仙傳 lived on herbs and refined mercury for a century and still looked thirty, and who rode a green ox everywhere and would not give his name, so people named him for the ox. That is exactly the right comparison for a costume advertising hale old age. 素券先生, the Master of the Plain Contract, is plainly a matching allusion to some other legendary adept, but which one is no longer securely recoverable.

A false semblance dressed to seem the true, a feigned feeling shaped to pass for real.

The verse gives the game away in its last line. 假像如真像 (jiǎ xiàng rú zhēn xiàng), "a false likeness got up as a true one," and 虛情似實情, "hollow feeling passed off as real." The storyteller has spent five lines admiring the disguise and then tells you, in the sixth, that it is a lie -- so the reader watches what follows knowing exactly what the pilgrims do not.