Spooky Supplies

Spooky Supplies are a Draenor-specific Hallow's End currency. Five can be acquired each daily reset period. Use them to purchase garrison decorations.

Source
This item is a reward from the following quests:
 * Culling the Crew
 * Foul Fertilizer
 * Mutiny on the Boneship
 * Smashing Squashlings

As currency
Izzy Hollyfizzle at both Lunarfall and Frostwall sells holiday items in exchange for Spooky Supplies: