And the reply from the second expert:

>> I'm guessing that it is one of three choices:
>>
>> the long-legged bush cricket, Anabrus longipes (which is found in
>> northern Oregon, at least, and probably also Three Sisters);
>>
>> the Blair Witch Bug (based on your video);
>>
>> or proof that aliens bred with grasshoppers in the late Devonian (the
>> only evidence being the appearance and the subject heading).
>> I feel 99% sure about choice #1, until more evidence for the other
>> choices is found.
>>
>> I am reserving the 1% unless I have the species wrong altogether.

So I'm guessing it's a bush cricket.