Something I've never had a chance to do in a Cthulhu is call in an artillery strike on a Great Old One. That seems like it would be a lot of fun. Here we see a Twenties-vintage artillery computer, perfect for calculating the exact angle needed to plant a 150mm shell right between old Yoggie's eyes. Wait? What do you mean it doesn't have eyes? Aieeeee...!!!
(Oh, and this is also a great bit of cool retro-tech for pretty much any bit of pulp-related visual inspiration.)