South Africa spearhead Kagiso Rabada claimed the prized scalp of Steve Smith and gave Australia's skipper a spirited send-off in Port Elizabeth, where the tourists collapsed to be 6-170 at tea on day one of the second Test.
A fired-up Rabada, who already has five demerit points because of a string of indiscretions including last year's send-off of Ben Stokes that led to a Test suspension, screamed in Smith's face as he brushed past him in celebration.
The express paceman then removed both Marsh brothers in his next over, lifting the Proteas' hopes of a series-levelling victory.
Smith, who unsuccessfully reviewed after being trapped lbw on 25, looked decidedly unimpressed with the physical contact.
Umpires, having put both captains on notice pre-match to ensure their players behave better compared to the acrimonious first Test in Durban, had a long and stern chat with Proteas captain Faf du Plessis after the incident.
The dismissal of Mitch Marsh, who batted at No.7 instead of No.6 because of a gastro bug, ended the second session and capped a shocking collapse of 6-72.
Earlier, David Warner and Cameron Bancroft shared a 98-run stand and did well to see off the new ball in tricky conditions.
Footage of Warner's staircase stoush in Durban took the gloss off Australia's series-opening win and ensured all eyes would be on the vice-captain on Friday.
Smith's decision to bat ensured his understudy was thrust into the thick of it from the outset.
Du Plessis described it as a good toss to lose, confident his pacemen would be incredibly potent given the dark clouds, morning rain and some eight millimetres of grass left on the St George's Park pitch.
Australia reached 0-18 after 13 overs as deliveries routinely beat the bat, amid stifled laughter and gasps of disbelief from the slips cordon.
The morning session ended when Bancroft was out edging for 38, undone by a full outswinger from Vernon Philander.
Warner was clean bowled for 63 shortly after the meal break, victim to a sensational delivery from recalled paceman Lungi Ngidi that kissed the top of middle stump.
Smith and Shaun Marsh steadied temporarily in a 44-run stand before Rabada removed them both lbw.
