From the manga/anime series Kateikyoushi
Hitman Reborn. What you enter after being shot with a
Dying Will Bullet if you feel regret about something you didn't do before
you died. In Dying Will mode, the physical and psychological limits of the body are removed, and the person in the state will act out whatever it is they regretted, regardless of the physical or social consequences. Dying Will flames will come out of the person's forehead, and their clothes will apparently melt off (thought the underwear remains intact).