I saw this large beetle when I was walking on the cliffs recently. I didn't know what it was but thanks to Google I discovered that it's a Black Oil Beetle - they have a weird breeding cycle -
The females dig burrows to lay their eggs and their larvae rely on nearby vegetation to complete their strange and rather gruesome life cycle. When the larvae hatch, they crawl up onto the vegetation and hop onto passing feeding bees. The larvae then hitch a ride back to the bee's nest and eat the bee's eggs and its store of nectar and pollen. It emerges as an adult ready to mate and begin the whole cycle again.