I can't really think about Halloween, or Samhain, if you prefer, without thinking of the ballad of "Tam Lin," especially this part:
"And pleasant is the fairy land,
But, an eerie tale to tell,
Ay at the end of seven years
We pay a tiend to hell;
I am sae fair and fu o flesh,
I’m feard it be mysel.
"But the night is Halloween, lady,
The morn is Hallowday;
Then win me, win me, an ye will,
For weel I wat ye may.
"Just at the mirk and midnight hour
The fairy folk will ride,
And they that wad their true-love win,
"Tam Lin" Child Ballad 39A.24