The shark suit was really cute & fit my 53 female body really generously (it was not too tight) .  I built a cone shaped head piece out of cardboard, covered it in tape, held it on with long shoe laces that tied around my shoulders and in front under chin. This held the head up.  The 1st thing I had to fix on the shark before I even wore it, was 1 of the eyeballs was so crooked and overstuffed, I had to take a lot of stuffing out  & re-sew it. I would have sent it back, but I wanted to wear it to a Whale Festival days later.
Went to the festival & played shark & took pictures with people & danced to a Tom Petty tribute  band.  It all went well, (suit is hot, but not as hot as fur costume). The face lets in a lot of air.
Big con:  Zipper came undone on the bottom & the threads came apart.  I just finally went to try to repair the zipper & turned the costume inside only to see that the foam is extensively ripped all over and around the legs.  I hope that this will not cause the fabric of the outside of the shark to rip.
Positive side:  the shark is really cute & funny & people respond with good vibes; both adults and kids loved the shark.  I danced, but not crazy or anything,  I also bent down to hug a little kid & I think that is what caused the foam to rip, but I didn't feel it rip & the suit did not seem tight.
The legs are funny because of the design of the shark, to make it look like a shark.
If you really want to be a shark, this could be a good base design if you sew & reinforce the zipper before you wear it, especially at the bottom.  I also made the fin in The back to stand up by bending a wire hanger to put in there, attached it to a rectangular piece of cardboard, (3x6 approx) attaching the wire by puncturing it through the cardboard & taping it.  If you can make the head, sew the zipper &fix the fin to stand out, then this would be a great costume & last longer.  I don't think the ripped foam in the legs will ruin the costume, but it does suck.  Happy Sharking! And Spread Good Vibes !