Yea, it's a root. I've had a phal do this, the new root grows up, & over, then quickly down thru the leaf, or thru the space btwn leaf & stem, so it just looks like that from this point-of-view. However, usually, if you look around you will find the green root-tip(s)... Or the tip hasn't grown enough to have poked out yet... Or it's an older root, and a new tip will restart to grow whenever it feels like it (Lol)... (which could wait & resume growing in the spring.) I have one Phal doing this now... It's got a few root-tips shooting out below where it's roots have done this. Not sure why they do this, but I only have that one orchid that has a couple of these wierd roots, its an amboinensis x tetraspis hybrid, yet none of the roots on my species orchids seem to grow like this, and I have a couple of each species (flava & reg)
... It kinda reminds me of one of those Loch-ness monster pics... The ones where u see humps (like the back of a snake/eel shaped "monster" in the shape of an "M", w/ the top part of the "M") sticking up out of the water... Or is that just me? Lol