Sorry, I must of forgot. It's to prevent its flame from turning into a purple color and causing the same effect which occurs on Halloween (hope this helps)
Maybe change the name, “the killer pumpkin” sounds a bit overrated and childish, because a lot of people just add “the killer” to something to make it sound scary. But other than that, GREAT IDEA!
The Killer Pumpkin; Safe; Once per month a single pumpkin must be destroyed in its room; The Killer Pumpkin is a standard pumpkin first found in ▇▇▇ on Halloween. It has a candle inside of it that seems to never run out. When the date becomes the 31st of October, the pumpkin's candle turns into a blue roaring flame and causes all nearby Halloween related objects/creatures to be improved drastically.