Five people have been arrested after a violent brawl in a supermarket involving a man dressed as Spider-Man.
Video footage posted on social media showed a woman staff member being kicked in the throat and punched in the face by the man in the costume.
The Metropolitan Police said they were called to an Asda near Clapham Junction, south London, at 10.40pm on Thursday following reports of a disturbance.
In the video, people could be heard shouting, and one woman yelled "Oh my God!".
A second clip showed fighting in the warehouse area, with several people in Asda clothing and others in costumes.
Someone in a wheelchair appeared to be near the melee.
The man in the Spider-Man costume also looked to be using a crutch to hit people with.
A woman in her 20s was taken to hospital with minor injuries, while another five people were treated at the scene.
Two men aged 37 and 35, an 18-year-old woman and a 17-year-old girl have been arrested on suspicion of affray and violent disorder.
A 31-year-old man was arrested on suspicion of actual bodily harm, grievous bodily harm, affray and violent disorder.
An Asda spokesperson said on Friday: "We are aware of an incident which occurred at our Clapham Junction store late last night.
"We do not tolerate any form of violence or abuse towards colleagues or customers and we are working closely with the police in their inquiries."
The GMB trade union said its members were among those involved, and that representatives were at the store on Friday to offer support.
Senior organiser Mark Wilkinson said: "GMB cannot condemn strongly enough the actions of these people and we thank the police for their swift action in arriving to help protect our members from further harm.
"The video footage is absolutely horrifying and we are offering whatever support is necessary to any member who were affected during the incident."
He added: "Sadly, GMB is all too aware that whilst Clapham Junction is an extreme example, attacks on retail workers are on the increase. Parliament needs to act now to toughen the law."
Information can be reported to the police by calling 101 or tweeting @Metcc using CAD 7883/22Jul