This video is a Christmas themed screamer first uploaded to YouTube around Christmastime of 2009. The original uploader is RIPFILMS, the same makers of OMG Decapitated Head Prank. The video starts off normal enough, with footage of (likely the maker's) cat climbing about a Christmas tree for most of the prank. At the 0:39 mark however, its face becomes slightly sinister and it lets out a harrowing meow before cutting off.
NOTE: The following video contains a screamer.