יָשׁ֣וּב עֲמָל֣וֹ בְרֹאשׁ֑וֹ וְעַ֥ל קָ֝דְקֳד֗וֹ חֲמָס֥וֹ יֵרֵֽד׃
His mischief shall return upon his own head, And his violence shall come down upon his own pate.
Read kabbalistic (mystical) interpretation of Psalms 7:17: and classical mystical sources.