Merlin doesn't mean to touch the lizard creature.
It's a complete accident, but when Arthur stabs it to death he's pretty much in flailing range and he might, ever so slightly, have flailed a hand against it.
Which is, unfortunately, about as much contact you need to end up with the uncontrollable ability to read people's thoughts.
Arthur's scowling down at him, looking from Merlin to the dead monster with an unhappy scowl.
All Arthur's thinking, in that hectic, confusing moment, is that he really, really hopes Merlin can't read his mind.
But then suddenly he's not just thinking that, he's apparently thinking everything else. It's a blunder of thoughts, all panicked and tripping over each other, broken and jumbled. Occasionally there's a flash of his face, his voice and he thinks perhaps his skin, quickly trampled on and overwritten by smeared out thoughts about the palace, and Uther, and, for some bizarre reason, his own boots.
//Dear God, don't be hearing any of this.//
"Merlin? You touched it? Can you hear what I'm thinking?" Arthur doesn't look happy about the idea in the slightest.
So Merlin makes a split decision.
He pulls his face into something confused and sore-looking.
"What? No, I mean, I don't think so...think something."
Arthur very carefully thinks about Uther, it's a very forced sort of repetition inside his head. Though he does slip once and think about the time he accidentally saw Morgana's left breast, that time she left the screen in her room tilted at just the right angle.
"Nope, nope, I can't hear anything, or see anything, or whatever," Merlin says carefully. "It must have worn off when it died."
He doesn't miss the way Arthur relaxes, ever so slightly, before covering it with a huff of impatience.
Then Arthur's thinking that he's secretly glad Merlin's not hurt, though he also thinks he looks untidy sprawled on the stones, and he very much wants to kiss him until he looks even more untidy.
Merlin carefully blinks at him.
Arthur scowls back.
"Well, are you going to lay there all day or are you going to get me something to eat."
"I'm going to get you something to eat," Merlin hazards, apparently he doesn't win a prize for guessing right.
Merlin has learned a lot things he never expected during his two days as an accidental mind reader, which is about half as long as it seems to last, some of them more disturbing than others.
Servants know everything. Really, they do, it's terrifying.
Uther's brain is a very, very disturbing place, where everything is warped and mutated by his hatred of magic and his need to protect his kingdom. Sometimes he dreams he turns into a monster and eats Arthur.
Merlin's started avoiding him as much as possible.
Morgana likes to imagine ways to creatively murder different people in the castle that annoy her. Merlin is now forced to accept that she's imagined killing him every single time she's been cross with him.
Gaius thinks about dead animals far, far too much.
Gwen gets songs stuck in her head, constantly.
Oh, and Arthur wants to have sex with him.
It's very distracting, because Merlin isn't necessarily against the possibility of Arthur having sex with him.
Though Arthur's never given any indication that he wants to outside of his focused and occasionally filthy brain. Merlin’s starting to worry that he's just hallucinating it all.
Arthur is currently not thinking about sex with him. He's thinking about his armour, which he's piling up in Merlin's arms, like he won't fall over if balanced too much on one side, and complaining about Merlin's ability to make him look like a prat in front of anyone within range.
Though he'd protest that 'making him look like' is a bit of a stretch, since Arthur doesn't always need help there.
"You insulted me and generally made yourself look like a complete disaster, which can't help but make me look like an idiot by default. I think I deserve-"
//I deserve you damn it, damn everything, why must you make everything so difficult!//
Merlin rubs the middle of his forehead and pretends the solid huff of surprise he makes is frustration, frustration rather than- god anything else.
"Merlin, are you even listening?"
"What? Yes, of course, of course I'm listening." He smiles, in case that helps.
It obviously doesn’t.
Arthur thinks his mouth is ridiculous and far too fond of back-talking him, and all full of insults that hide behind his stupid little smile.
Arthur quite likes his mouth.
He thinks, quite graphically, of a use he'd quite like to put it to and Merlin drops absolutely everything he's carrying.
Arthur watches the armour cascade to the floor, watches Merlin blink in startled shock for a handful of seconds.
"You heard that didn't you?" Arthur says quietly, and his face is almost completely unreadable.
"Heard what?" Merlin has bluffed his way out of worse situations than this before. He's bluffed his way out of certain death, this is nothing.
"You heard what I was just thinking."
"No, I didn't." Merlin fidgets.
//Stop fidgeting, it makes you look guilty.//
Merlin immediately forces his hands to still.
Arthur lifts an eyebrow as if to say 'got you.'
"You're a liar," Arthur says under his breath. "A filthy liar. I've been suspicious for a few days now. You're better at hiding things than I thought you were." The last is flung out as more of an accusation.
//I think perhaps you should be punished.//
Merlin makes a noise because he knows he's in trouble, knows he's in so much trouble.
Merlin moves his hands to do exactly that without thinking about it, fingers skittering over Arthur's bare chest, and Arthur huffs like it's more proof.
"We're going to talk about this tomorrow." Arthur clearly wants to be fierce, but his voice is heavy, too thick to be anything angry.
"Tomorrow," Merlin says faintly. But then Arthur looks at him and he can't talk at all.
"But you're forbidden from holding anything I might think against me."
"I wouldn’t do that," Merlin says quietly.
//Take my shirt off.//
Merlin slides his hands underneath, fingertips against the warmth of Arthur's skin, he pushes the red fabric over Arthur's head and lets it fall behind him.
//Though should you decide to act on any of them, that will be entirely your own choice.//
Merlin thinks maybe he could get used to Arthur's voice in his head after all.