I made Sam's costume out of brown felt. It has a zippered front and a tail, tethered with fishing line to the back collar to keep it up and moving with him.
His mask is a foam monkey face I found at the craft store. I simply cut out the eyes and punched holes for a ribbon to tie it on.
I thought the banana was the crowning touch, but Sam says the tail is the best part. Everyone loved Sam's costume.
This is NOT Sam's Halloween costume. He has already chosen to be the Black Knight, but with 13 days left, that may be subject to change. It's not unusual for Sam to have a couple of costumes.