Chester P. Runk was a genius physicist who developed a matter transporter, which imploded and became a part of his body. He became a living black hole, capable of sucking matter into another dimension. After a couple of bizarre tussles with Wally West, the two became friends.
I've only read a handful of issues with Chunk, including the Geoff Johns story where the black hole inside him threatens to devour all of Keystone. It was a nice way to bring back a long-lost cast member, and to show all the fans that he's doing quite well for himself.
I really don't have much to say about Chunk. I mean, it's no secret that I love superpowered physicists, and I love the Flash and his supporting cast. Combining the two can only lead to success. Hmmm...hey, Marc Guggenheim, I have the perfect cast member for you! His sheer awesomeness might be just enough to pull that book out of the gutter!
I mean, even a living black hole can't suck as much as the last seven issues.
Sigh...I miss Wally, but I really miss Chunk.