David is still MIA. I think he may be lost in the Australian outback or something.
Other possible reasons:
In the hospital with koala poisoning
Koala's can be dangerous!
A Koala bear walks into a bar, sits down and orders a sandwich.
The Koala eats the sandwich, gets up, spins around, pulls a pistol out of his pouch, shoots the piano player, and proceeds to walk out of the bar.
The bartender, in shock, shouts to the Koala, "Hey, who do you think you are, you ate my sandwich and shot my piano player, and just where do you think you're going!?"
The Koala replies, "Hey, I'm a Koala. Look it up."
The frustrated bartender pulls out a dictionary from behind the bar and looks up Koala:
The dictionary said "n. a marsupial that eats shoots and leaves."