There were some pretty terrifying scenes after Gremio's 3-1 loss to Palmeiras on Sunday.
The home side's fans invaded the pitch at the Arena do Gremio after the full-time whistle had been blown and attempted to destroy the VAR area.
Gremio players had to take refuge in the tunnel and dressing room as the chaos was unfolding outside.
The small collection of supporters also tried to fight with stewards and threw punches as things turned very, very ugly in Porto Alegre.
Take a look at footage of the incident here...
Video: Gremio fans invade the pitch after Palmerias defeat
Chaos, complete and utter chaos.
The fans were eventually returned to the stands when the riot police arrived on the scene and managed to calm things down somewhat.
There was still a significant amount of damage done, though.
The violent response from Gremio fans is down to the fact that the team are really struggling in Brazil this season and currently occupy one of the spots in the relegation zone.
Gremio's struggles in Brazil this season
Their defeat to Palmeiras means they're now 19th in the table with just 26 points to their name and seven from safety.
They only have 11 more games to play in Serie A this season, meaning that relegation is starting to like a very real possibility.
Up next for Vagner Mancini's side is a trip to current table-toppers Atletico Mineiro, who've lost only five games all season.
Gremio have lost three times as many and if they don't buck up their ideas sooner rather than later, they'll be playing football in Brazil's second-tier next campaign...