They were running. Nothing new there; they were always running. The Doctor and Donna always running for their lives, running right into danger and then running away from it until the Doctor came up with some sort of ingenious plan. Or they got captured and taken hostage as they had done on a couple of the planets that they had ended up on. Donna could list them all in her mind, as well as the stupid reason that the Doctor had got them imprisoned for.

Anyway, they were running. Just to emphasise the point some more, they were running away from something very large and very angry. To be precise, the thing that they were running from was called a Cathchat, as the Doctor had expertly informed Donna right before he had angered it by sitting on its precious egg. It had instantly awoken, motherly instincts kicking in, making it the most terrifying creature within that particular solar system, its eyes glaring up a ferocious yellow, baring its moss-stained teeth through black lips, shaggy black fur bristling on angered ends. It was quite like a giant, ugly, vicious cat really. Unfortunately, the Doctor wasn't a cat person and Donna had allergies. The Doctor idly wondered, as he set off on his long-legged sprint, if he should ask anyone who came on board the TARDIS about any medical problems they had or had previously experienced, because it might save him a lot of trouble and one less slap. Maybe he could create some sort of form…

Of course, as he continued running, the Doctor realised that this would never happen. He hated paperwork and he'd never actually read what people had written down. Altogether, the entire idea was a waste of vital seconds that he could have been using to think of a way out of their current predicament.

He threw a quick glance over his shoulder at Donna, who was powering her way forward just behind him, eyes focused, red hair trailing in the air behind her, like a bright and billowing flag insistent on showing the raging Cathchat where they were. Even though there was very little light in the underground labyrinth where they had found the creature and although both his and Donna's eyes had adjusted to this circumstance, the Doctor knew that the Cathchat could see perfectly.

Feeling the need to ease the situation as the running continued, the Doctor slowed his pace to match Donna's.

'I think we're losing it,' he said, his breathing unaffected. The sounds of the creature were still echoing through the twisting cobalt caves, but it sounded more distant, further away. Maybe it had become bored of the chase.

'Well we wouldn't 'ave to lose it if you 'adn't gone and sat on its bleedin' egg!'

'I thought it was a rock!' the Doctor defended himself meekly. 'A strange, pulsing rock…'

Donna let out a frustrated groan, but was silenced from retorting, hazel eyes wide, when the pounding of the Cathchat suddenly became nearer.

'On second thoughts, maybe we're not losing it,' the Doctor decided, picking up the pace again. 'Come on Donna!'

'Hang on!' she shouted back at him as he was rounding a corner. He jogged backwards back around the bend and, still jogging on the spot, asked;

'What for?'

'My shoelaces are undone.'

'Oh, human devices have the most perfect timing!' he sighed, running back to where Donna was on her knee fiddling with the wriggling white string and shaking hands. 'Why don't you just get Velcro?'

'Easy for you to say, your shoelaces never come undone!' She paused halfway through tying the laces, staring at the Doctor's neatly laced white converse. 'Why is that?'

'Because I've done this,' the Doctor told her, pulling his sonic screwdriver out of his pocket and swiftly swooping down to Donna's level, before buzzing it over both of her shoes, making them glow blue. He stood up and tossed the sonic screwdriver so it rotated several time sin the air before placing it back inside his pocket. He glanced down the tunnel where the sounds of heavy footsteps were getting louder, but slowing down. 'There, they'll never come undone again now.'

Donna took his pro-offered hand and stood up again.

''Ow the hell do I get them off then?!' she demanded.

'No time for that, run!' He dragged her off after him as he raced back around the bend, before suddenly stooping. Donna stumbled forward.

'Sorry,' he said briefly, not looking at her. Once again, his hands flew up to his inside pocket, rummaging around for a few seconds.

'You'll be sorry in a minute when that thing eats us,' she told him.

The Doctor let out a bark of laughter. 'Don't be silly, it won't eat us… Just maybe disembowel us and leave our bodies on his master's front door stop as a present… A-ha! Got it!'

Donna stared in disbelieve, partly at what the Doctor ha just rattled off, but also because he was now pulling a long line of orange wool out of his pocket, using both of his hands to pass it through.

'What?' she managed to get out.

'I once had a penchant for scarves… Think I'd prefer purple now though…'

'No, I think you misunderstood me… I meant, what the-?'

The Cathchat roared at their scent.

'Oi, language, Miss Noble!' the Doctor scolded, the line of wool now all bundled in a matted ball in his hand.

He hopped back around the bend, pulling Donna with him. The Cathchat immediately saw them, its massive frame filling the entire cobalt corridor.

'Watch,' he instructed, before tossing the ball of wool at the creature, who immediately pounced. Donna closed her eyes tight and flinched, preparing herself for what was to come. But nothing did. She warily opened one eye and was met with a strange seat.

The giant, ugly, vicious Cathchat was playing with the wool, threading it through its claws and making a calm noise that could only be described as a purr.

'Cats, they're all the same,' the Doctor said. 'And they all want to attack me…'

'Yeah, they're not the only ones…' Donna muttered.

'Come on,' the Doctor said, starting off at an easy stroll away from the delighted alien creature. 'I think we'll be better off above ground.'

Donna turned to join him, throwing one last disbelieving look at the monster that had been eagerly hunting their blood just moments ago.

'Interesting thing about Velcro,' the Doctor started as if nothing had happened. 'It wasn't actually invented on Earth because it was-,'

'I don't care about that right now, Doctor,' Donna interrupted. 'The only thing I care about is the fact that my shoes are now permanently stuck on my feet because of you!'

'Ah, well-,' he stuttered.

And he was running again, away from Donna, if possible, even faster than he had been running from the Cathchat. He was keen to avoid being slapped, especially over something as trivial as shoelaces.

……

A/N: So, this idea came to me as I was staring at somebody's Converse on the train yesterday. It was pretty easy to write, and fun too, so I hope you enjoyed it!