(Photo: Eurobeat Kasumi Photography)
Koneko, a cosplayer who calls herself "Your Average Nerd," made this far above average costume of Thor, God of Thunder. She wore it last month at Katsucon.
Her Mjölnir was made not by the dwarves of Nidavellir, but by the employees of PropNerd Props, who are, to the best of my knowledge, human.
You can see more photos of this marvelous cosplay at Fashionably Geek.