The Doug-o-saurus is the name given by some for the gigundasaurus a long extinct behemoth from the planet Kerona.  The bones of the creature can be found in the Keronian desert. Its height when full grown averaged to hundreds of meters., the Doug-o-saurus in its current configuration are about 7-meters in height (which suggests possible width for the creature).
The skeleton of such a creature was so large that its cavities were inhabitable by creatures such as the Orat, or provided access to the Keronian Underground Cities.
This may be the remains of one of the ancient sentient but extinct Grell a third species of grell found on the planet which died off eons ago, perhaps when the planet had a more temperate environment.
The Doug-o-saurus has long worm/snake-like body, but appears to have two set of short arm-like appendages (which seperates it from the modern Grell). Modern Grell vary between a reptilian species (which perhaps shares closest anatomy to the gigundasaurus) but without any known appendages, and a species that looks closer related to the sandworms of Arrakis. The modern reptilian grell may represent an evolution from the larger gigundasaurus species.