This is one of the 'Immortal' masks from the 300 spoof Meet the Spartans. It's basically the same as the Immortal masks from 300 except they are all grinning instead of having the evil frown. These were made by the same people that made the masks for 300, using the same manufacturing techniques.
Here they are in the movie. The face-off in Meet the Spartans was a 'You got served' style dance-off. Some of the masks had some extra stupid features like big teeth or a big tongue hanging out (yeah, it's a pretty stupid movie…).
