Brazilian flyweight Allan Nascimento died Monday after an apparent heart attack, UFC said in a statement. Set us as preferredBrazilian UFC flyweight Allan Nascimento has died after suffering an apparent heart attack in his sleep, the organization announced. “Our thoughts and deepest condolences are with Allan’s family, friends, teammates, and loved ones during this incredibly difficult time,” UFC wrote on social media. It was there that he was given his nickname, Puro Osso, which is Portuguese slang for “skin and bones.” As soon as people saw me, they called me ‘Puro Osso.’