A larger chunk of rock to hurl at Cavemen. The Hunk is best used against tanks with high health. It deals massive damage with a long cooldown, so make sure not to use it against a single, weak caveman.
One Hunk not enough? No problem! You can also unlock a Double Hunk which fires a second hunk of boulder that lands shortly behind the first one. Keep that in mind when targeting the Double Hunk.