The pancake carry is a specific type of sand bag that you will carry at a spartan race. Pancakes also go by different names such as SandBells and most Spartan Races will have 20 lbs. for the women and 40 lbs for the men.
A pancake carry, like a sandbag carry, means you will be picking up the weight assigned to you and carrying it up and down some terrain until you get back to where you started. You can carry it many different ways – many people will carry it on one shoulder, alternating left and right shoulders, other will carry with both hands in the upper center of the back. When exhausted the way you will see people carry it is on their head, which can cause some back pain in the long run and I wouldn’t suggest it.
There is a pancake or sandbag carry obstacle at every single spartan race. I suggest you practice running with some weight prior to your spartan races or this obstacle will gas you in a surprising fashion.