The Clark Bar is a candy bar consisting of a crispy peanut butter/spun taffy core, originally with a caramel center, and coated in milk chocolate. It was the first American "combination" candy bar to achieve nationwide success, and is now similar to the Butterfinger and 5th Avenue bars. The Clark Bar was introduced in 1917 by David L. Clark and was popular during and after both World Wars.
A disappointed customer shares his experience on Amazon, "Clark Bars absolutely SUCK! I had tried the first two " equivalents " of a Clark bar, Butterfinger, and 5th Avenue bars and since I liked them both I had to try Clark bars and was SORELY, SORELY DISAPPOINTED. These bars are just no good, something is wrong with the chocolate coating and while the peanut butter isn't bad the taste doesn't mesh and it amounts to a horrible eating experience. Take your money somewhere else and buy a box of 5th Avenue bars, they're by far the best of the peanut butter candy bar offerings."