These spiney cacti are known as Chollas. Lets just say that they don't look as dangerous as they are. We have one of these in our front yard (desert landscaping) and a sad little bird had the misfortune of flying too close. He was stuck in there for a while.
This photo is from Joshua Tree National Park.
chollajoshua tree national parkhdrtrespasstrespass phototrespass photographysunsetcactuscactijoshua treewww.trespassphotography.comDrew Metzger