Bar Kappara (possibly Eliezer haKappar, possibly his son Shimon) was a tanna who was known, within the Talmud, for his unusual antics and unchecked speech. In Nedarim 51a, he causes Rebbi to laugh out loud by placing a basket upside-down on his head, while rash words in Moed Qatan 16a cause Rebbi to rebuke him. He is rebuked by Rebbi in more than one place in the gemara, but the most intriguing is in the Yerushalmi's gemara to the same mishna in Moed Qatan.
There (Moed Qatan 3:1, 81c), the Yerushalmi has him delivering a riddle to Rebbi via Rebbi's unlearned son-in-law. The context, we are told, was that a group of sages were asking learned questions of Rebbi, and Bar Kappara told Rebbi's son-in-law (Bar Elasah) that he should ask something too. When Bar Elasah related what Bar Kappara told him to ask and Rebbi saw Bar Kappara grinning, he rebuked him strongly.
Here is the text of Bar Kappara's riddle, as delivered by Bar Elasah. What follows is my own attempt at a translation:
שאול משמים נשקפה הומיה בירכתי ביתה מפחדת כל בעלי כנפים ראונו נערים ונחבאו וישישים קמו עמדו הנס יאמרו הו הו והנלכד נלכד בעונו
Ask the following: "From heaven she gazes, pining in the corners of her house. She terrifies all winged creatures. Young men saw us (?) and concealed themselves; aged men rose and stood to attention (?). Oh! Oh!, they cry. He who is caught is caught in his transgression."
My translation is probably pretty awful: I can't figure out what to do with ראונו (they saw us??), nor how to understand הנס if it is qualifying עמדו. But most importantly, I have absolutely no idea what this passage means, nor why it was offensive to Rebbi.
First of all, I would very much appreciate it if somebody could correct my translation, either by breaking the text up differently or showing me where my understanding of any word within it is wrong. And secondly, if anybody knows of a good peirush on this text, or has their own interpretation as to what it means, that would be lovely.