Though I usually don't show saguaro-shaped mailboxes, this one is worth an exception! Gregg Townsend spotted it along the route for Cyclovia on April 6th.
The “arms” are covered with... spark plugs. A search with Bing tells that, naturally enough, you'd take your vehicle here for service. The business is Arizona Radiator and Muffler Service.
Thanks for the prickly art, folks. And thanks too, Gregg, for taking the time to get off of your bike and snap some photos!