"Sure, just plain, or -?"

"Does it come in varieties? Could we try several?"

"Yeah sure! Any allergies?" Kettle corn, cheddar, lots of butter, hm what else.

"Kib?"

"I am not known to have any allergies."

"We should all be good, then." 

"I need a token something, the language doesn't work for it..."

"Yes, I put together a list earlier of poetry recommendations and linguistic history records, but I don't have it on me, can you fetch yourself a copy as payment? First item on the list was Curufinwë Fëanáro's 'on the aims of a united theory of Quenya syntax' -"

"Mentioning it exists counts. Deal," says the demon, and he makes three buckets of popcorn.

"Thank you so much. Do you have any friends who would like Quenya and Thindarin and an embarrassingly vague smattering of my world's human languages?"

"Oh yeah, you want the membership list of my linguistics club?"

"I would love it!"

So the demon provides it.

And the demon can go home! 

He vanishes!

"What's an allergy?"

"Humans have this thing where their bodies will mistakenly interpret harmless substances as deadly poisons and then overreact in response, sometimes by for example their throats swelling up until they choke to death."

He munches popcorn.

Kib also tries the popcorn. He gravitates toward the cheese kind.

When the popcorn is all eaten they will leave.

That's fine.

And go outside and flop in the grass and sing miserably for three days straight.

He doesn't do that. He goes to his room and solicits cuddles.

Kib finishes the movie and reads the novel and the cultural footnotes and watches another movie and goes downstairs for dinner.