I asked a couple of white-dwarf aficionados, and neither recalls seeing any star with these features (nor does Jim Kaler, who wrote the book on stellar spectra). Far to the red, those certainly look like the Ca II infrared triplet, but very strong and broad. There are also similar absorption lines roughly matching the sodium D-lines (5890, 5896 A), and close to the bright night-sky line at 5577 A (but not the 6300/6363 ones also from [O I]). Then there are the huge absorption bands around 5150 A, 5300, and 6400 A. It may or may not be significant that there is a normally-weak quartet of Ca II absorption lines around 6400 A. Objects in adjacent fibers don't show any funny business which indicates contamination by light of bright objects or a problem with the sky subtraction. The absorption features are so deep compared to the continuum that it's no help trying to make the spectrum by superimposing two stars, since that would only make the absorption deeper in one star and not allow very much filling-in by the other star. Read more