Biggest shocks you have seen in football management games

After Macclesfield's shock win against Palace, it's a good time to bring out this topic!

SM26:
FA cup: Birmingham City made the final while playing in the Championship, the season they somehow won the playoffs and got promoted to the Premier League. However, they lost the cup final to Fulham on penalties.
In another season, City lost to a league 2 team in the third round. The same also happened to Chelsea.
Premier League: Brentford got relegated with an 87 rated Mainoo. I signed him up for my team.
Ligue 1: In one save, Stade Rennais, who hasn't won a league title before, won the league in the 2029/30 season. In another save, Nice, who hasn't won since the 1950s, won the 2028/29 league title, and PSG somehow finished third in that same season.
La Liga: In one save, Real Sociedad won the league twice in 3 seasons.
Champions League: In one save in the 2029/30 season, Arsenal got eliminated in the league phase.

SM25:
Champions League: I have seen Real Madrid and PSG got eliminated in the league stage before. Arsenal almost got eliminated in one season.
Premier League: Everton got relegated in the 2026/27 season, despite having a squad with a lot of 83+ rated players. All of them were eventually sold.