Just Stop Oil protesters saw the tables of disruption turned as a rowdy stag do hijacked their demonstration in London.
The eco-protestors were on a slow march near Waterloo Station on Friday and brought traffic to a standstill when the stag interrupted them with chants of, "we love you oil, we do!".
The group of lads also ripped one of the banners carried by the protestors, swirling it in the air before running off.
One of the men was dressed in bright pink and adorned with a Pride rainbow garland and fluffy halo headpiece, as he joined in on the march punching his fists in the air, yelling the chants.
Pals then cheered as he ripped the orange banner with the protestors' logo on it and threw it on the ground.
The bizarre exchange was caught on camera, with activists staging a demonstration outside Parliament on Friday lunchtime.
It comes days after several of the climate change campaigners disrupted a cricket match at Lord's, resulting in three arrests.
England star Jonny Bairstow tried to physically carried one of the protestors off during the pitch invasion on Wednesday as activists threw their trademark orange powder across the green during the second Ashes test.
Judit Murray, 69, Daniel Knorr, 21, and Jacob Bourne, 26, were all charged with aggravated trespassing and are due to appear before Westminster magistrates' court at the end of next month.
A Metropolitan Police spokesperson said on Friday: "Police were made aware of 15/20 Just Stop Oil #protesters walking slowly in York Road at 12:20hrs, causing serious disruption today, Friday, 30 June.
"Officers were on scene at 12.23hrs and issued a condition to move off the carriageway, which was complied with immediately."
A JSO spokesperson said: "Today, 25 students are marching in Waterloo to demand that the UK government immediately halt all new fossil fuel licences."
