Itztli "Obsidian" a Deity made of obsidian and stone, famous for trying to kill Tonatiuh and failing. You can say he can't fool you because, you'll just see right through him... He wasn't always cold and made of stone, he was once Tlahuizcalpantecuhtli, but took a dart to head for fighting Tonatiuh and converted into what we see here. He is also a variant of Tezcatlipoca god of the night.
GutterAztec courtesy of Gutter Cat #1637