This band is Limited Edition 5000 and only available to guests who attended the Mickey’s Not So Scary Halloween Party! starting on September 1st, 2014. These bands do make a special noise when using the FP+ touchpoints at the Magic Kingdom. It was sold at the Frontierland Trading Post and the Emporium for $29.95 each.
It’s the first custom MagicBand ever to be sold at a hard-ticket paid special event, as well as the first band sold to the public to feature Mickey and Minnie. Disney’s merchandise SKU barcode for this MagicBand is 400008949620.
https://www.youtube.com/watch?v=Qk9ok11OvPY