Weird void glitch!

I was checking out the epic dens when I came across Ilovemydogsmurphandtank 's den!
There is a GLITCH IN THERE!
Here is a pic!i
Cool or what!
anyway I went to explore futher into the den.
It was a pretty cool den, with game machines scattered about and other cool stuff, but no more glitches!
There was a cute penguin plushie though!
So I went looking for MORE den glitches!

There is another void, this time in bubbledoo1 's den.
Its basicly a pile of toys but with a black box around it....
The first one was clearer but this one is more interesting.

I REALLY want to know how to do this!
Please comment and tell me if you know, Ill do a special mention for you!