  We report optical observations of the VY Scl star BZ Cam during its previous
optical low state in 1999/2000. We find drastic variations in the line
profiles. Narrow-band imaging observations show that its nebula extends farther
than previously known and seems to be composed of two components. We determine
the [OIII] line intensity of BZ Cam's nebula to 4.8 * 10^-13 erg/cm^2/s. We
discover a proper motion of BZ Cam of 25+-2 mas/yr which together with the
systemic radial velocity yields a space velocity of 125 km/s. We re-interpret
the nebula as being photo-ionized by hypothesized transient, luminous,
supersoft X-ray emission during optical low states, and shaped by the
transverse motion of BZ Cam.
