He looks & acts fine, but he has his leg twisted, like when you wring out a dishcloth. What's it doing? Is this normal? I never noticed it do this before. Maybe it's finally going to split. It's really big, like a cantelope or honey dew melon.
My large one looked like this too, he worked it out on his own. I think it is flow or just opening up and closing or something like that. I've seen it a half dozen times, no issues.
