搖身一變 He Shakes Himself And Changes
好魔王，他也有七十二變，武藝也與大聖一般，只是身子狼犺些。欠鑽疾，不活達些；把寶劍藏了，念個咒語，搖身一變，即變作八戒一般嘴臉。抄下路，當面迎著大聖，叫道：「師兄，我來也。」好魔王，他也有七十二变，武艺也与大圣一般，只是身子狼犺些。欠钻疾，不活达些；把宝剑藏了，念个咒语，摇身一变，即变作八戒一般嘴脸。抄下路，当面迎着大圣，叫道：「师兄，我来也。」
逐句解 Line by line
A fine Demon King! He too commands the seventy-two transformations, and his martial art is a match for the Great Sage's; only his body is the more ungainly.
好魔王 is the storyteller's admiring shout, the same one he uses of the Great Sage, and here it goes to the Bull with no irony in it at all. 狼犺 láng kàng is a street word for bulk that gets in its own way. 身子 ends in the light 子, zi.
He lacks the drilling quickness, and is the less nimble;
What the Bull lacks is speed of a particular kind. 鑽疾 is quickness that drills through — the exact opposite of 狼犺 — and 活達 is suppleness. The source punctuates this run oddly, with a full stop after 狼犺些 where the balance wants a comma, then a semicolon running on into a clause that is not balanced at all. The three deficiency-clauses are kept exactly as the edition divides them.
He put his precious swords away, recited a spell, shook himself and changed, and at once took on a face and features just like Eight Rules'.
藏 is the verb here, cáng, to put away or conceal. The reading zàng that this edition uses elsewhere covers the name 三藏 and the sense of a hoard — Chapter 59 has fifteen occurrences and every one is the name. This is the first time in the whole Fiery Mountain sequence that the character is a verb.
He cut down by a side road, came face to face with the Great Sage, and called out: "Elder brother, here I am."
抄下路 is to cut off the highway by a short cut, the same 抄 that stands behind the street spelling 綽 in the next passage. That is 當面 for the second time in three passages — and this time the Bull is using it of the deception rather than of the honest demand he decided against.
The storyteller's 好魔王 is the hinge. It is the formula reserved for a figure about to do something worth watching, and handing it to the Bull tells you the impersonation is to be admired on its own terms. He is not a fool blundering into a trick; he is as good at this as his opponent.
The concession that follows is exact about where the difference lies. Both have the seventy-two transformations; their fighting is level. What separates them is 狼犺 against 鑽疾: bulk against the quickness that bores through. It is a physical distinction, not a moral one, and it explains every fight in the sequence without making either of them the better creature.
Putting the swords away is the last of the day's losses and the only one he chooses. Since morning the Bull has lost his mount, his armour and the goodwill of both households; the swords are his first wife's, taken up in her cave that same day, and now he hides them himself so as to look like a man who carries a rake.