Vampires can't get sick. This is, essentially, one of the fundamental rules of being a vampire. They can't catch viruses or diseases, they don't get fevers, they don't even get colds. Vampires are immune to just about every mortal sickness.
Marshall Lee is sick.
Well, it's not so much that he's sick as that he's exhausted. Frighteningly exhausted, like he's gone a week without eating or sleeping but his body still wants to move. Two days have passed since he, Fionna, and Cake fought the ketchup ghoul, and despite the fact that his role in the fight had been a relatively small one his entire body feels sore and uncomfortable. He's feels so incredibly tired, but when he lies across his bed his skin itches like there's bugs scuttling around just under the surface, and he wonders if he can claw his way out of his own flesh, like a snake shedding its skin.
All he can do is huddle under his blankets and wait it out.
After they'd reached Marshall Lee's house, Fionna had taken him inside and had nearly dragged him to his room. She'd stepped out for a few minutes, blushing, to let him change into more comfortable clothes before she'd pushed him into his bed and tucked him in. All of this was done to the soundtrack of Marshall Lee alternating between growling at her in embarrassment and groaning in pain.
Fionna hasn't checked up on him since then, but then again he's been asleep almost the entire two days since she'd dropped him off, so if she has visited he wouldn't know. Cake shows up after the first night, when the moon is high in the sky, and at this time Marshall Lee would normally be pulling pranks and playing his guitar, but all he can do is hiss at her groggily when she checks to see if he has a fever.
("Of course I don't, you stupid cat, vampires don't get sick."
"Yeah okay, honey, whatever you say.")
But she's soon gone and Marshall Lee curls up even more on his bed, determined not to move. When he does his skin scrapes against the sheets harshly, every nerve in his body hypersensitive to the point where the soft cotton feels more like harsh sunbeams baking his flesh.
He dozes for the most part, long hours of sleep interrupted by brief fits of half-lucidity where he ponders what's driven him to this point. Over exertion. The sudden and unwelcome reintroduction of blood into his diet. Emotional backlash, possibly. The most likely culprit is the tomatoes.
Marshall Lee freakin' hates tomatoes.
He blames the tomatoes for everything; they are the reason he's so achy, and he later decides that they are the reason he doesn't really put up much of a fight when the Ice Queen blasts through his roof and carts him off.
Marshall Lee awakes to the frigid feeling of ice beneath his body, thankfully numbing most of his pain, but his limbs are still too heavy for him to move. He tries anyway, and the agony of the movement causes him to curl inwards with a gasp. He lifts himself up on shaky arms and tries to determine where he is.
It's not that difficult to find the answer, considering he's in a jail whose bars are made out of ice, in a room of ice, presumably in a castle of ice. Marshall Lee is understandably confused, because while the Ice Queen kidnapping dudes is a fairly normal practice, she usually sticks to taking princes.
Marshall Lee is not a prince. He's worked too hard for too long to be a mere prince. No, Marshall Lee is a King.
The Ice Queen has never tried to pull anything like this on him, probably because among the magical community Marshall Lee is notorious for being incredibly unsympathetic to people assaulting him. Looking back on it, he thinks that he should have expected an attack along these lines, but he would have thought that it'd be another vampire going after his crown. (Metaphorical crown. Marshall Lee doesn't wear crowns, they don't go that well with his usual striped shirts. And he's not sure that it would fit on his hair anyway.)
