My love for the Aztec is still plain to see as I bring yet another Aztec diety back to life as a giant monster. This one just happens to be deader.
Mictlantecuhtli (try saying that 5 times fast) is the Aztec god of the dead and the underworld, known as Mictlan. His name is ltierally 'Lord of Mictlan'. He is often depicted as skeletal, and is associated with darkness, owls, bats, and spiders. Not much is said about his powers.
His kaiju depiction was fairly easy. Just use various hats attributed to him, give him his necklace of human eyeballs, and make him a skeleton! All in a day's work. And it does work marvelously.