Supernatural (TV series)/Recap/S04/E07 It's the Great Pumpkin, Sam Winchester

Season 4, Episode 7:

It's the Great Pumpkin Sam Winchester
A witch is sacrificing people so as to raise the demon Samhain. The demon's rise would mean the breaking of one of the 66 seals, so Castiel and Uriel get involved and warn Sam and Dean to take care of it quickly.

Tropes

 * Bald Black Leader Guy: Uriel.
 * Did Not Do the Research: "Samhain" is a Celtic word pronounced roughly "sow-en", and is the name of a fall holiday, not a demon.
 * This is more accurately classified as Artistic License, as their spot-on description that "The Celts believed that October 31st was the one night of the year when the veil was thinnest between the living and the dead" indicates they did do the research, and likely included the demon origin for story purposes. As for pronunciation, Sam looking up a word in an ancient text and mispronouncing it is entirely plausible. Until angels pronounce it exactly the same way.
 * Stock Scream: Part of a Wilhelm is heard while Dean is staring at a mask in a Halloween shop and.