These masks are made once a year in Loy Province as part of this big 'reproduction ceremony.'
As for the masks, they are supposed to represent all the evil spirits and bad-ness in the village. They are meant to look as ugly and scary as possible. At the end of the festival, they ditch all the customs into the river, symbolizing getting rid of all the evil spirits.
But in the last 20 years or so they realized they can make a lot of money by selling them away to unsuspecting tourists . . .
If you listen in the background, you wont hear Thai music. It is actually Cambodian music sung by a very famous singer nicknamed 'The Cambodian Ray Charles.' The translators told me his song was about demons, so it was very appropriate I think.