I am not real sure how a candy bar becomes influential but here goes.

Time Magazine has released the 13 most influential candy bars of all time.  Here is the top 5 with an explanation of how it is "influential."

  1. Kit Kat. "Beyond being the first candy bar to be marketed around sharing, which helped turn chocolate into a social snack, Kit Kat was also the first to gain a global following."
  2. Hershey's Milk Chocolate. "Nestle may've invented milk chocolate, but Hershey's made it mainstream.  By building its factory right in the middle of dairy land, [they] powered an unparalleled distribution network."
  3. Toblerone. "Debuted in 1908 [as] the first bar to debut with a filling."
  4. Nestle Milk Chocolate. "Prior to this bar's introduction in 1875, bar-form cocoa was bitter, chewy, and dark."
  5. Snickers.  "More than 80 years after its launch, this is the world's best-selling [candy bar].  Although it may not have revolutionized candy bar taste or distribution, it's unparalleled at selling itself."

Check out Time.com for the full list of The 13 Most Influential Candy Bars of All Time.