This is apparently from nature:
Glass melted in a fire:
No, not a digital glitch, it's carved like that:
Marlon Brando Before and After His Makeup Was Done for His Role in the Godfather
(I'm often amazed at what actors are permitting themselves to be made up to look like, given that most audiences will assume that "that's how he looks now!")
Cross-section of undersea cable. Dang.