Legend Of Korra: Will It Bend!

[dehro]

This is a bit of a case of the pot calling the kettle black. We've only seen Energybending happen once and that was the Avatar doing it to the most powerful firebender in the world who was under the influence of Sozin's Comet. For all we know, Energybending might look different every time, or at least when it's not done by the Avatar or on a Sozin's-Comet-influenced firebender.

twice actually. first time was when the turtle-lion imparted energybending to Aang. the exact same greenish flashes happened even then. I'd say that something we actually see twice is statistically more relevant than watching Amon do his thing and not seeing anything happen visually which we've come to expect from bending... could it be a new and secret form of bending? possibly. is it energybending? unlikely.
we have no reason to believe energybending to change colours or "visual rendition" every time
1 because none of the elements work that way and that is a valid precedent as far as we know. there is no precedent that allows us to think otherwise.
2 because it would make things harder to understand to us the public, breeding confusion and inconsistency. this show is targeted towards children and is a cartoon. out of necessity it builds on visual consistency to make itself understood. bending is pretty much colourcoded for our convenience
3 because the only reason to even consider the idea that energybending comes in a variety of colours and forms is to force through the possibility that Amon is energybending in some misterious way that is inconsistent with what has been shown already.
sozin's comet amplified the range of firebending and that's it. it didn't bend reality. Aang has never had a personalised graphic rendition of any element he's ever bent. there's no reason to believe that if anybody else is capable of energybending, it should happen in a different colour. these are not lightsabers.
Occam's razor tells me that out of the two possibilities, energybending is not the right one.
for all we know, I'm on a horse.

it's just not possible to tunnel through certain ground.

how do you come to that conclusion?
tunnel, no.. bending..
bending the ground is pretty much the definition of earthbending. even metalbending happens because of tiny particles of ground mixed with the metal. tunneling underground is precisely what badgermoles do