This has really been bothering me recently... Its probably a very simple question.... But, here it goes....

Anyways, recently I've noticed this crazy sound more and more often in some music (Not mine.... I wish it was), and was wondering what in the world it is... I'm thinking its some sort of pedal, but I have no clue. To me it kinda sounds like someone tapping then sliding that tap up the neck, but its done so fast that it cant be humanly possible, so, Then I get to thinking its some fancy tremolo work, but, when I think about it, it begins to make less sense, for one reason, a few of the examples I'll give I'm fairly sure they dont have a tremolo (Though, I could easily be wrong... Ive yet to play with a tremolo, so if its that no need to execute me)

Anyways, Heres some examples,

Muse - Citizen Erased, at about the 4.20 mark (I dont think Matt has Tremolos on his guitars AFAIK)
Scorpions - Rock You Like A Hurricane (In the solo... Fairly early)
Theres a few more examples that I cant quite track down though, I know there is a Steve Vai song that has that, but its in such a manner that it has to be a pedal..... I mean he is Uber awesome at guitar, but that would require his hand to move like 6 directions at once... I cant think of the song right now....

Hopefully you guys have an idea of what im talking about.... Its really bugging me.
Life is like an Empty Box, there could be something exciting in it at first look, but upon further review, well, it's empty.

The Muse song sounds like an octaver. Or a really fast slide up the neck
Crap, someone help me out here