A recent Google search leading here was "why does frank mullen do that thing with his hand." Frank Mullen is the vocalist of Suffocation, and "that thing he does with his hand" is what I call "death metal spirit fingers." If you're unfamiliar with spirit fingers (the non-death metal kind), refer to the cultural institution known as Bring It On:

http://www.youtube-nocookie.com/v/YDbnkfHtD_E&hl=en&fs=1&rel=0

Surprisingly, spirit fingers translate well from cheerleading to death metal. See this video for Suffocation's "Abomination Reborn," where Mullen does death metal spirit fingers at 0:12 and 1:07.

http://www.youtube-nocookie.com/v/i6nrglujp1U&hl=en&fs=1&rel=0

Mullen does death metal spirit fingers only with his left hand, and only in response to blastbeats. You can see him do them from 0:15-0:19 in the video for "Surgery of Impalement" and all throughout this video of him onstage with Napalm Death, starting at 0:45.

http://www.youtube-nocookie.com/v/Zi10J8rljZE&hl=en&fs=1&rel=0

As for why he does them — well, because he's awesome. Death metal spirit fingers: learn them, love them, don't leave home without them.

- Cosmo Lee