Question about giant ladybugs.?

My sister has a problem with a nest of giant ladybugs. They're extremely aggressive. I looked it up and the only thing I could find was grapevine beetles but they're bigger than that. They're about the size of a fist and they bite. She remembers our greatgrandmother had some and burned the nest because she said they would destroy everything. Does anyone know what these are or have seen them before? They are very frightening.