Dug up this massive, alien-looking bug while turning the soil. It has a huge bald head, thick legs, and a striped abdomen. It looks terrifying. What is it?

If you have disturbed the soil while gardening, especially in moist and sheltered spots, you may have inadvertently uncovered their habitat. Their presence in your garden is an indication of healthy soil, as they contribute to the ecosystem by breaking down organic matter.