Board Thread:False Info and Speculative Discussion/@comment-4091815-20160218215625/@comment-5379216-20160222073336

NishHound wrote:

it might be mason because corey felt something was wrong when kissing him, but also on the other hand the beast was resurected on the night of the supermoon when scott was dead and mason was right next to scott during that time. The Beast wasn't resurrected on the night of the supermoon. In the beginning of 5x10, a night before the night of the supermoon, the Beast runs around Beacon Hills and ends up throwing the BBHS sign through the building's roof.

But we do know that the DDs had plans about the supermoon, which is why I personally don't think it can be Mason.