The metalhead is a cave dwelling reptile, and no they’re not named for their appearance, while looking absolutely metal they’re actually named that for their roar. Their roar sounds very similar to a metal guitar. It is their way of communicating with others being unable to see. It is believed they were once domesticated, kept as pets by the ancestors of the Wryvirra trained to sing and perform since they are relatively docile around mostly humans and humanoid species. Because they are blind they can tell them apart just by how we communicate. Some might say that some remnants of the ancient Wryvirra or modern Wryvirra living in ancient ways are still around and these guys are still domestic to explain their docile behaviour.
It’s possible that their appearance was a result of selective breeding as scientists gathered evidence that their true colouration is more white-grey or pink rather than black with skull-like patterning on the head.