Roger's dead plant. He affectionately tries to bring it back to life, calling "Betelgeuse, Betelgeuse, Betelgeuse!", to no avail.
Betelgeuse is the second brightest star in the constellation Orion and the tenth brightest star in the nighttime sky. Space Quest 6 makes reference to the fact that the similarly-named lead character of the phonetically-pronounced Beetlejuice movie and cartoon appears whenever you called his name three times.