Ireland's Bundee Aki was sent off during his side's Six Nations finale against England in Dublin.
With less than 20 minutes on the clock, England No.8 Billy Vunipola charged at the defensive line, with Aki lining him up for the tackle.
But the 30-cap centre got it all wrong, making contact with the head of Vunipola, leaving the England juggernaut sprawled out on the floor and in need of attention.
There was immediate concern from players near the collision and medics rushed onto the field as play was stopped.
After checking with television match official Romain Poite, referee Mathieu Raynal felt he was left with no choice but to show the red card, despite the brief protestations of Johnny Sexton.
Explaining his decision, Raynal said: "There is no mitigation. There is no sudden drop in height. He decides to target him high and makes direct contact to the head.
"That's a red card."
Aki becomes the first Irish player in history to be sent off twice after receiving a red during the 2019 Rugby World Cup.
He is the second Ireland player to head for an early shower in the 2021 Six Nations after Peter O'Mahony was sent off against Wales.
Ireland were leading 26-6 when Aki left the field on Saturday. England scored a try almost straight away through Ben Youngs but Sexton hit back with a penalty soon after.
It was 29-11 to the hosts heading into the final 10 minutes, before ending 32-18 to the Irish.
