Watch Bignattydaddy for Free: How to Stream the Movie Online at 123Movies. . Bignattydaddy became a viral internet sensation. At 15 years old, he chronicled his body building on social media, openly flaunting the fact he was on steroids - a controlled substance, illegal without a prescription in the USA. This film follows him as he explains why he does it and how he deals with those who criticize him.