A/N: I've had a proliferation of Halloween-type ideas lately... here's one of them :)
As a child I lived in a town with many cemeteries and was eventually introduced to the 'game' of holding one's breath whilst passing by. I randomly thought of that at work recently and figured there must be the usual superstition behind that so I looked it up. Thus we have this, my own warped version ;)
*A tiny explanation of the concept behind bits of this (feel free to skip/read later): it is an old belief that one's breath contains some of their soul and lots of superstitions cropped up around that idea.
Merlin stopped abruptly, looking at the hill with dread.
"You're not going that way, surely."
Arthur, halfway up the incline, turned and arched an eyebrow.
"And why would I not, Merlin?"
The servant shifted his weight, discomfort evident despite the gloom of night.
"The cairns are that way," his voice was low, as if that would make any difference, "it's bad enough passing a graveyard during the day, but it's almost midnight."
"And?" The royal prompted impatiently.
"Well, you know..." he drifted off, fidgeting with the bags he was carrying until the warrior sighed dramatically.
"You don't seriously believe in that 'soul stealing' nonsense. It's for scaring children!" The pale man opened his mouth to argue, but was cut off, "And I see it has worked! Now stop being a girl's petticoat and catch up."
"Will you at least hold your breath?"
"Merlin..." he frowned, "you're not going to let this go, are you? Fine, I'll hold my breath. Happy?"
"I'd be happier if we could go another way."
"Then it's a good thing that I'm the master here and it's my happiness that matters- not yours."
Much grumbling later, the two crested the hill and looked down at the small collection of burial mounds. The simple tombs had been there long before Camelot was built and had a large number of superstitions attached to them- hence their undisturbed and overgrown state. At this particular time Merlin was worried about wandering spirits said to steal the souls of passerby to keep them company in the afterlife. He had seen such spirits on more than one occasion while growing up and had only avoided their attention by holding in his soul- his breath.
Pressed on by Merlin's nervous pace, the two were nearly clear of the dreaded vale when Arthur saw fit to exhale loudly. "See? Nothing to worry about!"
The warlock's eyes widened at the sight of a wisp headed straight for his charge.
"Arthur!" Merlin tackled the other man and covered his mouth and nose, hastening to cease his own breathing. The knight, oblivious as ever, had other plans and violently elbowed the slighter man in the stomach.
"Honestly, Merlin, I- Merlin?"
The younger man writhed, choking on the being of pure ice that had entered with the involuntary gulp of air taken when Arthur's strike had landed.
"Merlin, what's happening?" The blond knelt beside his friend, completely at a loss.
Pallid lips opened wide and two lights floated out; a shapeless, ethereal white seeming to drag an incandescent blue orb shot through with gold and silver.
"You-" Arthur gasped, looking worriedly between the familiar sphere and his motionless companion. Now holding his breath for an entirely different reason, the royal pressed a hand to Merlin's chest as his fingers sought a pulse beneath the ever-present neckerchief. "No... no, nononono..."
The warrior growled, drawing his sword and chasing after the luminous forms. "Give him back!" He swung his rune-etched blade at the white, the wind of the sword's passing pushing the two out of his reach. "Merlin! Fight it!" More spirits had begun to gather, drawn by the commotion. Excalibur cut through the cloud, managing to banish a few though most floated out of harm's way.
The gold brightened, drowning out the blue for a moment, and the wisps seemed to burn away.
Arthur gave a short laugh of relief and jogged forward with a smile.
Something was wrong; the gold had not just returned to its previous level, but had continued to dim. In fact, the entire ball was growing faint.
"Merlin?" His gaze jumped to the body and, seeing no obvious change, returned to the flickering light. "Stay with me, idiot. I'd never forgive myself if- just don't go-" the blue winked out despite his desperate supplications.
Calm down, he probably just returned to his body. All I have to do is go over and wake him.
Lowering himself gently, as if afraid to startle the man, he stretched out one trembling hand and laid it atop Merlin's heart.