He was paid in his own coin/ hoist with his own petard
By metaphor: the scheme devised against others ultimately worked against its originator. The evil planned turned against its planner.
("And Egypt prepared a snare for him (Exodus 14:27)... He was cooked in the pot he cooked in (the Egyptians planned to kill the children of Israel in the sea and in the end they drowned in the sea)" - Sotah 61a)
Translation
Expression (Hebrew)
בַּקְּדֵרָה שֶׁבִּשֵּׁל בָּהּ נִתְבַּשֵּׁל
Definition (Hebrew)
בְּהַשְׁאָלָה: הַמְּזִמָּה שֶׁרָקַם נֶגֶד אֲחֵרִים פָּעֲלָה לְבַסּוֹף נֶגְדּוֹ. הָרָעָה שֶׁזָּמַם פָּעֲלָה נֶגְדּוֹ.
("וּמִצְרַיִם נִסִּים לִקְרָאתוֹ(שְׁמוֹת יָד כז)...בִּקְדֵרָה שֶׁבִּשְּׁלוּ בָּהּ נִתְבַּשְּׁלוּ (הַמִּצְרִים זָמְמוּ לַהֲרֹג אֶת בְּנֵי יִשְׂרָאֵל בַּיָּם וְסוֹפָם שֶׁטָּבְעוּ בַּיָּם)"- סוֹטָה יָא ע"א)