笑出原嘴臉 The Laugh That Gave Him Away
這大聖忍不住，赥赥的笑出聲來。乾淨他不宜笑，這一笑笑出原嘴臉來了。卻被那第三個老妖魔跳上前，一把扯住道：「哥哥，險些兒被他瞞了。」老魔道：「賢弟，誰瞞誰？」这大圣忍不住，赥赥的笑出声来。干净他不宜笑，这一笑笑出原嘴脸来了。却被那第三个老妖魔跳上前，一把扯住道：「哥哥，险些儿被他瞒了。」老魔道：「贤弟，谁瞒谁？」
逐句解 Line by line
The Great Sage could not hold it in, and let out a snickering laugh.
赥赥 xī xī is a written-down giggle, two characters doing nothing but making the sound. The book has spent a whole chapter on Wukong's nerve and control, and undoes all of it with a noise.
He had no business laughing at all, and that one laugh laughed his real face right out.
乾 is gān, dry, and 乾淨 here is not clean but an intensifier — flatly, purely, he simply should not have. The narrator is scolding him, which is unusual and worth noticing.
Whereupon the third old demon sprang forward and seized him. "Brother! We were very nearly taken in by him."
The third seat. The roc, the one the book dressed in the whole first page of Zhuangzi and seated last — and he is the one who moves. His two brothers are still swatting at the fly.
The old fiend said, "Worthy brother, who took in whom?"
Four characters of pure confusion, and a small masterpiece of comic timing: the chief is holding a broom and has not caught up.
Everything in the disguise held. The face held, the badge held, the voice held, the story held twice. What broke it was that the trick was too funny and he was enjoying it too much.
That is the most consistent thing about Wukong across the whole novel. He is rarely beaten by a stronger opponent and very often beaten by his own delight. The book makes the point without moralising: it gives him one line of narration — he had no business laughing — and moves straight on.
Watch which demon catches him. The roc has said nothing for four passages while the other two panicked, argued and issued orders. This is the book quietly telling you who the actual antagonist of this arc is, and it will spend another twenty chapters proving it.