If you read down in the comments, the question of the chains has been asked several times. The common answer was Menards, although I lean more toward the Amazon Prime suggestion. Fact remains, wherever they came from, someone had to go down and wrap them around the dragon. Seems to me that task would have required…

Disney Land!

The question no one seems to be asking is: who went to the bottom of the icy lake and wrapped the chains around the dragon?