Sports gets people pretty heated, as they cheer for their team, drink beer and get caught up in the heat of the moment.
That's possibly the only thing we can say in defence of this one fan, who was in the crowd in Madison Square Garden to watch the Brooklyn Nets take on the New York Knicks.
The fan, who is well known as a regular attendee of Nets games and a vocal supporter of the team, seemingly got a bit too fired up as the local rivals came face to face and decided that he would hit another fan...with his prosthetic leg.
As a result, the security had to eject him (and the leg) from the premises by carrying him up the stairs and out of the arena. Unlikely to be his highlight of the season, we imagine.