In an image posted on Bayern's Twitter account, the Brazilian defender was seen dressed wearing a long Arabic shirt with a red and white checked headscarf, while carrying a package marked "caution".
The botched costume sparked an uproar on social media, and the club subsequently deleted the photo.
Instead, Bayern retweeted Rafinha's apology.
"Halloween is a scary celebration with exaggerated costumes, it was not my intention to anger anyone through my disguise or hurt someones feelings," wrote the Brazilian.
November 1, 2018