"Donna, run!" yelled The Doctor.
Donna ran. She ran as fast as she could, but was still no match for The Doctor, who was very much ahead of her.
All around them was the smell of mud and exotic plants. Roots and vines stuck out from all directions. These posed as obstacles for the Time Lord and his human companion in their goal of reaching the TARDIS, before a large reptilian creature catches up with them and promptly devours them without a moment's hesitation.
The beast had been enjoying a deep slumber inside its cave, when it had been rudely disrupted by these two travellers. This had left it in a state of incredible anger and it was also very hungry.
There was only so much adrenaline Donna's body could produce and soon her breath was beginning to catch. She glanced behind her to check how close the creature was on their tail, when she fell to the ground with a thud. She had tripped over a rock.
The Doctor heard the sound and called out to his companion. "Donna! Are you alri-"
Donna pulled her face out of the mud and wrinkled her nose.
"Eurgh. Yuck. That's just what I needed. An all-natural face mask made of smelly alien mud."
Pushing herself up to a standing position, she smoothed down her coat, brushing off a fraction of the filth and then wiped her hands on the enormous leaf of a nearby plant.
"Doctor, you'd better take me to the best outer space dry-cleaners next," she groaned at him. "Doctor?"
The Doctor didn't answer. Instead, he was crouching, with his hands over his throat, making rasping choking sounds, and then gagging as if he might throw up. "Oh my god. Doctor, are you okay? What's happened?" Donna exclaimed. The Doctor's face had paled. He was staring directly behind Donna and lifted his index finger, pointing.
Donna stood very still. Like a statue. She imagined she was one of the surrounding trees, trying to blend in with the jungle and be camouflaged. Another smell began to overwhelm her. The foul stench of hot breath was being puffed out by the very beast they had encountered moments ago.
Brushing past her, it stepped towards The Doctor and leaned down, its head almost as big as Donna. With a vicious snarl it bared its long fangs, tinged with brown and dripping with sticky saliva. Two nostrils flared in The Doctor's face, taking in his scent.
It was then, that an odd thing happened. The creature shut its mouth. A sort of whimpering sound came from it and it turned around and scarpered into the distance.
When she was sure it was safe to move. Donna knelt down next to The Doctor, no longer caring about the mud getting on her clothes. Placing a hand on his arm, she held eye contact with him.
"Are you okay?" she repeated. The Doctor nodded and stood up.
"I swallowed a fly," he admitted. Donna's face made a small round shape, resembling a smirk.
"Ooh," she said "That'll teach you, Spaceman, for running so fast with that big mouth of yours wide open."
The Doctor placed his hands in his coat pockets and frowned, looking Donna up and down.
"Come on," he ushered. "Let's get back to the TARDIS and find you some clean clothes."
Unable to turn this offer down, Donna walked with The Doctor back to the TARDIS, but not before making one joke at The Doctor's expense.
"There was an old Time Lord who swallowed a fly," she sang. "I don't know why he swallowed a fly. Perhaps he'll die."