Hahaa, I love how all cats know how to steal laptops.
It must be the heat they generate. If it's enough to fry the insides of the laptop, it's enough to keep a cat warm on a chilly November evening.
EDIT: Nevermind on the spider, I guess. It won't let me put two images for some reason. (._.)
If the image name has a space in it, replace it with an underscore. Worked for me.