The Milky Way bar's predecessor wasn't a single, specific candy bar. It's more accurate to say that it evolved from a series of earlier chocolate bars, each contributing to its development:

* "The Chocolate Bar" (1911): This was the first chocolate bar marketed by the Mars company. It was a simple milk chocolate bar, and the precursor to many of their future products.

* "The Milky Way" (1923): This was the first iteration of the bar that we know today. It consisted of a nougat center topped with milk chocolate. It was significantly smaller than the modern Milky Way.

* "The Big Bar" (1929): This bar had a larger nougat center with a milk chocolate coating and was marketed as a "big bar for a big appetite." It helped establish the larger size and familiar formula of the modern Milky Way.

So, while there wasn't a single, direct predecessor to the Milky Way bar, it evolved from earlier chocolate bars produced by Mars, culminating in the familiar and beloved candy bar we know today.