So, we never found out why DK was digging a hole in the back yard?
"He's been digging a hole in the back yard for a week, and won't tell anyone why."
They mentioned it twice in the last episode, like it was a mystery that would be solved later. But they never closed the loop on that one.
I guess it was this episode's MacGuffin...
Don't mess with me, man! I know karate, judo, ju-jitsu..... and several other Japanese words.