Gigi Hadid Assaulted and Manhandled in Milan

Gigi Hadid was manhandled by a notorious prankster Thursday in Milan ... and it was caught on video.

Gigi was leaving Max Mara's fashion show with sister Bella when Vitalii Sediuk grabbed her from behind and lifted her off the ground.

Bella scrambles to free her sis, while Gigi gives the guy an elbow.

Vitalii has famously found his way onto red carpets, kissing Will Smith, attacking Brad and Angelina, nuzzling Leo ... he even rushed the stage during the 2013 Grammys.