Arthropleura

Arthropleura is a genus of giant centipedes. It was not confirmed to appear in Series 5, but it could be the creature Hilary Becker was shooting at. (Episode 5.5)

Biology
The Arthropleura is a burrower. It has weak eyesight, but has very good sense of hearing and smelling. It is portrayed as a venomous creatures, however in real life, it was very harmless. It was also portrayed as about 20 to 50 feet long. This was way off the real size of the animal, which was around 10 feet, but this was done for a purpose to make it more menacing and scary.