A midrash in today’s daf yomi (Sotah 13a) tells the story of Chushim’s killing of Esav, when the latter was preventing the burial of Yaakov:
חוּשִׁים בְּרֵיהּ דְּדָן תַּמָּן הֲוָה, וְיַקִּירָן לֵיהּ אוּדְנֵיהּ. אֲמַר לְהוּ: מַאי הַאי? וְאָמְרוּ לֵיהּ: קָא מְעַכֵּב הַאי עַד דְּאָתֵי נַפְתָּלִי מֵאַרְעָא דְּמִצְרַיִם. אֲמַר לְהוּ: וְעַד דְּאָתֵי נַפְתָּלִי מֵאַרְעָא דְּמִצְרַיִם, יְהֵא אֲבִי אַבָּא מוּטָל בְּבִזָּיוֹן? שְׁקַל קוּלְפָא מַחְיֵיהּ אַרֵישֵׁיהּ, נָתְרָן עֵינֵיהּ וּנְפַלוּ אַכַּרְעָא דְיַעֲקֹב, פַּתְחִינְהוּ יַעֲקֹב לְעֵינֵיהּ וְאַחֵיךְ. וְהַיְינוּ דִּכְתִיב ״יִשְׂמַח צַדִּיק כִּי חָזָה נָקָם פְּעָמָיו יִרְחַץ בְּדַם הָרָשָׁע״.
The Gemara relates: Hushim, the son of Dan, was there and his ears were heavy, i.e., he was hard of hearing. He said to them: What is this that is delaying the burial? And they said to him: This one, Esau, is preventing us from burying Jacob until Naphtali comes back from the land of Egypt with the bill of sale. He said to them: And until Naphtali comes back from the land of Egypt will our father’s father lie in degradation? He took a club [kulepa] and hit Esau on the head, and Esau’s eyes fell out and they fell on the legs of Jacob. Jacob opened his eyes and smiled. And this is that which is written: “The righteous shall rejoice when he sees the vengeance; he shall wash his feet in the blood of the wicked” (Psalms 58:11).
This is a variant of the famous midrash I knew from elsewhere, in which Chushim lops off Esav’s head with a sword (not club), when it falls in Yitzchak’s lap (not Yaakov’s legs), and thus Esav’s head, too, is buried in Mearat Hamachpelah. Thus, Pirkei deRabbi Eliezer 39:14:
וכשבאו למערת המכפלה בא עליהם עשו מהר חורב לחרחר ריב, ואמ' שלי הוא מערת המכפלה, מה עשה יוסף שלח לכבוש במזלות ולירד למצרים, ולעלות כתב עולם שהיה בינם, לכך הלך נפתלי שהוא אילה שלוחה. חושים בן דן היה פגום באזנו ובלשונו, אמ' להם מפני מה אנחנו יושבין כאן, הראהו באצבעו אמ' לו בשביל האיש הזה שאינו מניח אותנו לקבור את יעקב, שלף את חרבו והתיז את ראשו של עשו, ונכנס הראש לתוך מערת המכפלה, ואת גוייתו שלח לארץ אחוזתו בהר שעיר.
When they came to the Cave of Machpelah, Esau came against them || from Mount Horeb to stir up strife, saying: The Cave of Machpelah is mine. What did Joseph do? He sent Naphtali to subdue the constellations, and to go down to Egypt to bring up the perpetual deed which was between them, therefore it is said, "Naphtali is a hind let loose" (Gen. 49:21). Chushim, the son of Dan, had defective hearing and speech, and he said to them: Why are we sitting here? He was pointing (to Esau) with his finger. They said to him: Because this man will not let us bury our father Jacob. What did he do? He drew his sword and cut off Esau's head with the sword, and took the head into the Cave of Machpelah. And they sent his body to the land of his possession, to Mount Seir.
These two start off relatively the same, but veer of at the end, in the ways I mentioned. The same idea is mentioned in Targum Pseudo-Yonatan on Bereishit 50:13. The pasuk:
וַיִּשְׂא֨וּ אֹת֤וֹ בָנָיו֙ אַ֣רְצָה כְּנַ֔עַן וַיִּקְבְּר֣וּ אֹת֔וֹ בִּמְעָרַ֖ת שְׂדֵ֣ה הַמַּכְפֵּלָ֑ה אֲשֶׁ֣ר קָנָה֩ אַבְרָהָ֨ם אֶת־הַשָּׂדֶ֜ה לַאֲחֻזַּת־קֶ֗בֶר מֵאֵ֛ת עֶפְרֹ֥ן הַחִתִּ֖י עַל־פְּנֵ֥י מַמְרֵֽא׃
His sons carried him to the land of Canaan, and buried him in the cave of the field of Machpelah, the field near Mamre, which Abraham had bought for a burial site from Ephron the Hittite.
and the rather lengthy, midrashic Targum:
וּנְטָלוּ יָתֵיהּ בְּנוֹי לְאַרְעָא דִכְנָעַן וּשְׁמִיעַ פִּתְגָמָא לְעֵשָו רַשִׁיעָא וּנְטַל מִן טוּרָא דְגַבְלָא בְּלִגְיוֹנִין סַגִיאִין וְאָתָא לְחֶבְרוֹן וְלָא הֲוָה שָׁבִיק לְיוֹסֵף לְמִיקְבּוֹר יַת אָבוּי בִּמְעָרַת כְּפֵילְתָּא מִן יַד אָזַל נַפְתָּלִי וְרָהַט וּנְחַת לְמִצְרַיִם וְאָתָא בְּהַהוּא יוֹמָא וְאַיְיתִי אוּנִיתָא דְכָתַב עֵשָו לְיַעֲקב אָחוּי עַל פַּלְגוּת מְעָרַת כָּפֵילְתָּא וּמִן יַד רָמַז לְחוּשִׁים בַּר דָן וְנָטַל סַיְיפָא וְקָטַע רֵישֵׁיהּ דְעֵשָו רַשִׁיעָא וַהֲוָה רֵישֵׁיהּ דְעֵשָו מִתְגַלְגַל עַד דְעַל לְגוֹ מְעַרְתָּא וְאַתְנַח בְּגוֹ עִיטְפֵיהּ דְיִצְחָק אָבוֹי וְגוּפֵיהּ קְבָרוּ בְּנוֹ דְעֵשָו בַּחֲקַל כְּפֵילְתָּא וּבָתַר כֵּן קְבָרוּ יָתֵיהּ בְּנוֹי לְיַעֲקב בִּמְעָרַת חֲקַל כָּפֵילְתָּא דִיזְבַן אַבְרָהָם יַת חַקְלָא לְאַחֲסָנַת קְבוּרְתָּא מִן עֶפְרוֹן חִתָּאָה עַל אַנְפֵּי מַמְרֵא
But when his sons had brought him into the land of Kenaan, and the thing was heard by Esau the Wicked, he journeyed from the mountain of Gebala with many legions, and came to Hebron, and would not suffer Joseph to bury his father in the Double Cave. Then forthwith went Naphtali and ran, and went down to Mizraim, and came in that day, and brought the Instrument that Esau had written for Jakob his brother in the controversy of the Double Cave. And immediately he beckoned to Hushim the son of Dan, who unsheathed the sword and struck off the head of the Wicked Esau, and the head of Esau rolled into the midst of the cave, and rested upon the bosom of Izhak his father; and the sons of Esau buried his body in the double field, and afterward the sons of Jakob buried him in the cave of the double field; in the field which Abraham bought for an inheritance--sepulchre, of Ephron the Hitah, over against Mamre.
Focusing on the first of these differences, sword vs. kulpa, just what is it? While the sword can lop off a head, the kulpa seems like a blunt force weapon, which can cause Esav’s eyes to pop out of his head.
Jastrow seems to take it as a Hebrew term, from the sense of peeling. Thus, a peeled pole, a lance, a strap, iron-pointed whip.
קוּלְפָא m. (קְלַף) 1) a peeled pole, lance. Sabb. 63ᵃ (expl. אַלָּה) ק׳ (Ar. a. Ms. O. קופל). —2) [peeled or scraped leather,] strap. Ber. 58ᵃ יהבו ליה ק׳ (v. Rabb. D. S. a. l. note 5) they gave him the strap, i.e. gave him the privilege of inflicting punishment; Yalk. Ez. 362 קיל׳. Ber. l. c. מחייא ליה בקוּלְפֵיה דפרזלא וכ׳ Ms. M. (ed. בקולפא only) he struck him with his iron-pointed whip and killed him; Yalk. l. c. בקיל׳. Keth. 65ᵃ מחתה לה בק׳ דשידא she struck her with the strap of a chest (Ar. בק׳ דשיראי with a silken strap).—Pl. קוּלְפֵי. Ber. 56ᵃ תרין ק׳ בלעת thou shalt receive two lashes. Men. 7ᵃ; Arakh. 22ᵃ, v. בְּלַע. Snh. 110ᵃ; Pes. 119ᵃ, v. קוּפְלָא I. —3) parchment, v. קִלְפָא.
Rav Steinsaltz notes one girsological variant, לקופינא דמרא.
We find this in Bava Kamma 27b, the handle of a hoe used to strike someone:
שלח ליה רב חסדא לר"נ הרי אמרו לרכובה שלש ולבעיטה חמש ולסנוקרת שלש עשרה לפנדא דמרא ולקופינא דמרא מאי
§ Rav Ḥisda sent the following question to Rav Naḥman: The Sages said that when one strikes another, humiliating him, the judges determine liability according to the following formula: For kneeing [rekhuva] him, he must pay three sela; for kicking, five; and for punching [velisnokeret] him, thirteen. The Gemara asks: If so for hitting him with the handle of a hoe [demara] and for hitting him with the top [ulkofina] of a hoe, what amount is one liable to pay him?
שלח ליה חסדא חסדא קנסא קא מגבית בבבל אימא לי גופא דעובדא היכי הוה
Rav Naḥman sent him the following response: Ḥisda, Ḥisda, are you collecting a fine for humiliation in Babylonia, where judges are not authorized to collect fines? Tell me how the incident itself transpired.
If original, fine. Otherwise, that might be some scribe trying to make sense of an arcane term.
Rav Steinsaltz traced the origins of the word to Persian, rather than Hebrew.
He asserts that the correct girsa of the word is kupla (referring to the girsot where this isn’t listed, but at least the peh comes first). The source is in Persian, kopal, whose implication is a staff with a thick head. He further notes that the Geonim described the kulpa as aa staff in which one head was thick, and within that thickened portion were nails or protrusions.
This could be a mace, or a morningstar. Here is a picture of a morningstar:
As for a mace, here is what Wikipedia has to say about maces and Persians:
Persians used a variety of maces and fielded large numbers of heavily armoured and armed cavalry (see Cataphract). For a heavily armed Persian knight, a mace was as effective as a sword or battle axe. In fact, Shahnameh has many references to heavily armoured knights facing each other using maces, axes, and swords.
Those maces are often ox-headed for the heroes of the Shahnameh.
and here’s a 19th century one from the Met:
And here is the Wiktionary entry on the Persian word kupal, which also mentions Babylonian Aramaic kulpa. I think Rav Steinsaltz meant that it was a scribal error, but we could also have metathesis, the transposition of two letters or sounds in a word, as a natural linguistic development.
For manuscript evidence, basically everything on Hachi Garsinan is קולפא. The one exception Rav Steinsaltz mentioned was Oxford 2675, which actually has both. In the main text, it has לקופינא, but has קולפא on the side. (Note the transposition of the lamed to initial position.)
Two other interesting variants on the page. Munich 95, as an obvious error, has Yosef, rather than Moshe, dealing with Yosef’s bones (first occurrence).
and Vilna Shas adds a Rashi on 13b, vayered Yehuda:
which is missing in Venice printing:
