  Abridged) In the SDSS, several unusual QSOs have been discovered that have
very blue rest-frame UV spectra but no discernible emission lines. Their UV
spectra strongly resemble that of the newly discovered quasar PHL 1811
($z=0.192$; $\rm M_{V}=-25.9$). With magnitudes of $B = 14.4$ and $R = 14.1$,
PHL 1811 is the second brightest quasar known with $z>0.1$ after 3C 273.
Optically it is classified as a Narrow-line Seyfert 1 galaxy (NLS1). Objects of
this class are generally strong soft X-ray emitters, but a BeppoSAX observation
of PHL 1811 showed that it is anomalously X-ray weak. The inferred
$\alpha_{ox}$ was 1.9--2.1, much steeper than the nominal value of 1.6 for
quasars of this optical luminosity, and comparable to the X-ray weakest
quasars. Follow-up {\it Chandra} observations reveal a variable, unabsorbed
X-ray spectrum and confirm that it is intrinsically X-ray weak.
