During the first night of WrestleMania 36, the main event saw The Undertaker against AJ Styles in a boneyard match. It was a very different match happening for fans, and there were moments in the match that were not planned.
According to What Culture, The Undertaker and AJ Styles’ talk during the match was “100% improvised.” It was also noted that the point where Taker cut his arm was an accident.
During the match, he cut his arm on the automobile window. Everything he said about the accident was also improvised. The crew liked how it was presented in the shot, so it was saved. This would explain why Taker’s arm was seen bleeding during the match. The cut was legitimate.