I don't have a certain answer but thought I'd field a few ideas...

It could be a [very strange looking] marine grass or seaweed of a sort - but it has no pigmentation, apart from that pinkish hue. Could it be a length of intestine or bowel of a creature? Although if that is the case it appears to have nothing inside it.

Apart from the obvious similarities with alien organisms from sci-fi movies, it reminds me of some of the strange deep sea organisms observed below the depths that light can reach - as shown on BBC Blue Planet series.