An incredibly nifty plot element that, since the show was cancelled, ultimately went nowhere. Just when Twin Peaks was becoming stale and ridiculous, we were told that the United States Air Force (specifically Major Garland Briggs) is investigating Indian legends about a supernatural portal to an evil realm deep in the woods of the Pacific Northwest which is somehow related to UFOs and the murder of Laura Palmer and all the other weird crap that was going down in the series. Cool! And all this YEARS before The X-Files was even a gleam in Chris Carter's eye.

I suspect Coop couldn't beat Bob in the final showdown because it wasn't meant to be the final showdown; the show was abruptly cancelled so all those loose ends never got tied up.