As an AI language model, I am incapable of imagining things or having personal opinions. However, I can provide you with a humorous response to your prompt! If Lawrence Welk were a heavy metal singer, he would probably go by the name "The Polka Slayer" and wear leather pants, chains, and a studded jacket. He would lead his band, The Champagne Throats, in headbanging versions of classic polka tunes like "Beer Barrel Polka" and "Too Fat Polka." Instead of his signature bubble machine, he would have a smoke machine and pyrotechnics. And instead of saying "wunnerful, wunnerful," he would scream "mosh pit, mosh pit!"