The shark tank is hell.
The first time I did a grappling shark tank I think I had to grapple ten men, most of them at least 40 pounds heavier than me, and I cried through about half of it. I did the whole thing, but I cried like a baby.
That was an extreme case when my body was already exhausted form two-a-days and I trained with a lot of people who didn't know how to adjust to training with people of different strengths and levels.
Still, the shark tank is pretty much a cardio nightmare no matter what, because the people you're sparring/grappling are always fresher than you. You are frustrated and your arms hurt. You hate it but you know it's going to make you better. My coach makes sound effects to make things more frustrating and makes you laugh right before your teammate throws a kick right to your gut. It's a good time had by all.
After I got home from practice today (which consisted of circuits and shark tanks) I ate two egg muffins and a pumpkin smoothie, a couple dates and some cashews. It was a weird meal. I was starving. Then I showered and passed out for two hours in bed with my cat. I had planned on doing homework all day. Shark tank had other plans.
I've been craving eggs a lot, so I had eggs again for dinner, with two paleo pancakes I made up that tasted like banana bread and and three pieces of bacon. And a candy cane. Christmas made me do it.