MIDRASH TEHILLIM
1.....(7.12)
...His mischief will return upon his own head.
that is, Haman's mischief, for everything which he contrived against Mordecai was returned upon his own head.
יָשׁ֣וּב עֲמָל֣וֹ בְרֹאשׁ֑וֹ וְעַ֥ל קׇ֝דְקֳד֗וֹ חֲמָס֥וֹ יֵרֵֽד
yoshuv ʿamolo verosho veʿal kodkodo chamoso yeyreyd
His mischief will recoil upon his own head, and his violence will come down upon his skull.
1.....(7.12)
...His mischief will return upon his own head.
that is, Haman's mischief, for everything which he contrived against Mordecai was returned upon his own head.