the joke is on someone

US /ðə dʒoʊk ɪz ɑn ˈsʌmˌwʌn/
UK /ðə dʒoʊk ɪz ɑn ˈsʌmˌwʌn/
"the joke is on someone" picture
1.

jenaka itu kembali kepada seseorang, seseorang menjadi bahan ketawa

used to say that someone who has tried to make another person look silly has in fact been made to look silly themselves

:
He thought he was being clever by tricking me, but the joke is on him now that I've exposed his lies.
Dia fikir dia bijak dengan menipu saya, tetapi jenaka itu kembali kepadanya sekarang setelah saya mendedahkan pembohongannya.
They tried to embarrass her with a prank, but when it backfired, the joke was on them.
Mereka cuba memalukannya dengan gurauan, tetapi apabila ia memakan diri, jenaka itu kembali kepada mereka.