wheel bug

I was feeling kind of sad that the wheelbug from a few weeks ago was brushed off of my car. I have been keeping an eye out for another. Today I was thrilled to see one on my patio chair. By the time I was ready to snap a picture, he was perched on my tomato plant. 
Later, he was scaling the door to the shed. He fell and landed in a web. The spider approached him. (Extra photo shows the spider's inspection.) I was hoping to see a battle for survival! But the spider knew better and left.
I don't know what it's doing. Maybe it's looking for a spot to lay it's eggs. I'll keep an eye out.