The parallaxed space textures make an ordinary sector become lethal.
There are two special textures called MOONSKY1
(#80) and BIGORBIT1
(#84). These are useful for creating a space-themed atmosphere. If
either of these textures are parallaxed on the ceiling or floor of a
sector, they will kill any player who enters that sector. If you want
to nullify the death effect, give the ceiling a palette of anything
other than 0. A value of 3 works great because it does not actually
change the texture's colour.