Left-handed Lightning Whelk

Busycon contrarium   4" - 5" 
It's rare for a sea shell to be left handed but this one is. 
 
Contrary to most gastropods (single one piece shells) which have a dextral aperature spiral on the right. Lightning whelk seashells have a sinstral aperature spiral on the left. 
 
These seashells are off-white to tan or gray with narrow violet brown stripes.
 
If you find larger specimens of this shell, they're usually white, tan or yellowish. We have found these shells along Florida's coast and the live ones bury down into the sand leaving the tip or canal of the shell sticking out. (Bare feet beware!) If you are hunting for seashells, please collect the empty shells and allow the live ones to roam. 
 
This carnivorous species finds clams as its main source of food using part of their shell and foot to pry open their prey.
 
They're found mainly around the gulf coast shores from Mexico to Florida and along the southern Atlantic coast up to South Carolina . Lightning whelks are usually in shallow water on sandy or muddy bottoms.