Shrivenzale
From TARDIS Index File, the free Doctor Who reference.
The Shrivenzales are large predators native to Ribos. They look something like flattened crocodiles, with green, rubbery skin, massive heads and stumpy legs. Shrivenzales have acute hearing and can hear ultrasonic sounds. The Shrivenzales sleep in the catacombs of Shur during the day, though they hunt smaller prey on the tundra at night.
The Ribosians keep a small Shrivenzale to guard the treasures of Shur during the nighttime. (DW: The Ribos Operation)
