Weird smell coming from new terrarium setup

[subtle_variegation]

Interestingly the smell was actually gone when I checked just now. If I had to describe it though it smelled like something rotting, almost putrid. But it wasn't that strong. Bad, but not overpowering.

However, there is a new development. There seems to be some mold forming in what looks like dried-up water that pooled at the bottom.

There's also this splotch on the side of the tank that has a bug in it. I don't know if it's mold but I don't think it was there before.