On some lecture footage of mr. Roth he says he developed a extra mustle for the clasic palm.has this happened to anyone else and if so how can I develop this mustle?

You can't develop an extra muscle (meaning create an additional muscle that is not already there), you can train the muscles that you already have. If you classic palm a lot, your palming muscles will develop so that palming is second nature. That is all he was saying.

Ooo I see!

I can actually grow muscles on my hand which allow the coin to be obscured by 'swallowing' it into the flesh.

Scary!