Well I saw a dog that looked like it was 150 pounds. I don't know what species it was, I think it was a Black Great Dane. I think it had a spiked collar too lol, might just be adding that in to my memory though (it was like a year or year and a half ago).
Edit: I thought it could be real, but that the dog wouldn't live very long at that "giantism"-like size. When I saw a Liger picture for the first time I thought it was fake.
I'm guessing that picture is fake though, because when I searched Hercules on the net there wasn't any info relating to that picture to prove it.