I forgot all about the extra service agreement that we signed with the contractor who installed our septic tank. During the day when our new system was installed, and while our yard was churned-up, a third guy came to our property in order to assess the soil. Most of the time, he was digging holes and trenches around the back yard; although, I did see him with a bicycle pump once or twice. He told me afterwards that we had a few pookas and a fire breathing dragon underground. He was able to get rid of the infestation by inflating them until they burst! Shown below is a photo during that work day.
I can't believe I nearly forgot about good old Dug.