Growth on branch - fascinated & disgusted

Quick...anybody know what this is on the stick in this photo? The huge stick (branch?) that blew off a tree and onto my car a few nights ago. I suppose I could Google it to satisfy my curiosity, but really what would I search? "Gross, bulbous brown row of growth thingies on branch?" "Brown shiny blisters on stick?" "Eeeeeew! Get it off my car?"

My inner child wanted to write the title for this post: "Can a stick give my car cooties?" but I elected to use something slightly different. Mildly more mature. (Not so mature, you'll notice, that it didn't get a bit of play on my blog. Heh. Inner child is alive and well, babies.)

But I am curious. As well as fascinated and utterly grossed out.

What is this stuff? And should I be alarmed that I used my bare hands to touch the infected stick as I removed it from my car?