Halloween Season is a seasonal event in Cookie Clicker, that was added in the 1.039 update.

The event was on during versions 1.039 - 1.0403 without a way to turn it off.

The seasonal event upgrade was added in version 1.041.

Since 1.0466 update Halloween season starts automatically and lasts from 24th to 31st of October (from 23rd to 30th of October for leap years).

Halloween season will be activated by purchasing the Upgrade "Ghostly biscuit", which will launch it for 24 hours.

The upgrade will be available after unlocking the Season switcher, which costs 1,111 Heavenly chips and baking at least 10 trillion cookies baked in the current game, that let you trigger seasonal events at will, for a price. 

The upgrade is repeatable, but will get more expensive every time you buy it, like Elder Pledge. It will also cancel any other seasonal event that is on at the time you click it.

When purchased, it will unlock the features of the Halloween season: Halloween-related cookie upgrades, and Halloween Wrath Cookies (Also known as "Scary Cookies").

Halloween-related cookie upgrades are only available by popping Wrinklers, which means that at least the One Mind upgrade has to have been purchased and the Elder Pledge is not in effect.

The appearance of Wrath cookies during the Halloween season:



List of the 7 known flavored cookies which may drop from Wrinklers during the Halloween season. Each flavored cookie has a base cost of 444,444,444,444 (444.444 billion) cookies.

Halloween cookies
Icon Name Unlock condition Base price Description ID
SkullCookieNew Skull cookies Minimum 5% drop chance from popping a Wrinkler during Halloween Season Money 444.444 billion Cookie production multiplier +2%.
"Wanna know something spooky? You've got one of these inside your head RIGHT NOW."
GhostCookieNew Ghost cookies Cookie production multiplier +2%.
"They're something strange, but they look pretty good!"
BatCookieNew Bat cookies Cookie production multiplier +2%.
"The cookies this town deserves."
SlimeCookieNew Slime cookies Cookie production multiplier +2%.
"The incredible melting cookies!"
PumpkinCookieNew Pumpkin cookies Cookie production multiplier +2%.
"Not even pumpkin-flavored. Tastes like glazing. Yeugh."
EyeballCookieNew Eyeball cookies Cookie production multiplier +2%.
"When you stare into the cookie, the cookie stares back at you."
SpiderCookieNew Spider cookies Cookie production multiplier +2%.
"You found the recipe on the web. They do whatever a cookie can."

The current drop chance is 1-f, where f is the fail rate. The base fail rate is 0.95, or 0.8 if the achievement Spooky cookies is unlocked. There are several modifiers which can further reduce the fail rate.

Modifier Factor
Green yeast digestives 1/1.03=0.970874
Santa's Bottomless Bag 1/1.1 = 0.9091
Starterror 0.9
Shiny Wrinkler 0.9
Selebrak, Spirit of Festivities 0.9/0.95/0.97 (Diamond/Ruby/Jade)
Mind Over Matter, Reality Bending, Both 0.8, 1/1.025 = 0.9756, 1/1.275 = 0.7843
Cosmic Beginner's Luck 0.2
Garden plants (mature, dirt) 1/(1+0.01G+0.01S+0.03K)
G = # of Green Rot
S = # of Shimmerlily
K = # of Keenmoss

For example, if you popped a wrinkler with the Spooky Cookies achievement and the Santa upgrade Santa's Bottomless Bag, then the fail rate will be:

$ f=0.8/1.1=0.727272 $

If you popped a shiny wrinkler with Mind Over Matter, Selebrak in Diamond slot and four Keenmoss in the garden, the fail rate will be:

$ f=0.95*0.9/1.25*0.9/1.12=0.549643 $

Cookie Spawn ProbabilitiesEdit


Upgrade Probability Distribution

Exploding a Wrinkler after it has begun to feed on the big cookie has a 5% chance of unlocking 1 of the 7 Halloween-themed cookie upgrades. If you have the Spooky cookies achievement, it increases to 20% chance. However, if the particular upgrade chosen at random is already unlocked, it will not unlock a new one. So on each Wrinkler explosion, the actual chance of unlocking a new cookie type is equal to:

$ s \cdot \left(1-\frac{N}{7}\right) $

Where N is the number of upgrades already unlocked and s=1-f is the success rate (0.05 normally, 0.2 with "Spooky cookies", 0.136364 with "Santa's bottomless bag", and 0.272727 with both). The table below shows how the success rate (r) effects the expected value of Wrinkler explosions needed to unlock all 7 Halloween cookie upgrades.

For example, with bare success rate (s=0.05), the expectation value is:

$ \frac{363}{20s}= 363 $

However, with "Santa's bottomless bag" and "Spooky cookies", s becomes 0.272727 and the expectation value drastically reduces to:

$ \frac{363}{20s}\approx 67 $

Probabilities for Halloween-Themed Cookies


Probability of Appearance

Formula Base



Spooky cookies



bottomless bag



Cookies & bag


0 s*7/7 5% 1/20 20% 1/5 13.6% 1/7.3 27.3% 1/3.7
1 s*6/7 4.29% 1/23 17.1% 1/5.8 11.7% 1/8.6 23.4% 1/4.3
2 s*5/7 3.57% 1/28 14.3% 1/7 9.74% 1/10 19.5% 1/5.1
3 s*4/7 2.86% 1/35 11.4% 1/8.8 7.79% 1/13 15.6% 1/6.4
4 s*3/7 2.14% 1/47 8.57% 1/11 5.84% 1/17 11.7% 1/8.5
5 s*2/7 1.43% 1/70 5.71% 1/18 3.90% 1/26 7.79% 1/13
6 s*1/7 0.714% 1/140 2.86% 1/35 1.95% 1/51 3.90% 1/25
Expected value for Wrinkler explosions to unlock all 363/20s 363 90 133 67

A method to get all the cookie upgrades quickly is to wait for a few wrinklers to spawn, wait for an autosave ("Game Saved" popup), pop the wrinklers quickly, and - if no cookie upgrade appeared - quickly hit F5 to reload before the game is autosaved again - the wrinklers will be back and you can try popping them again.

Another way, similar to the first, is to open multiple tabs with wrinklers, and pop the wrinklers on each tab until you get a cookie upgrade. Always leave one tab open with wrinklers, so if all the other tabs fail to give you a cookie upgrade, you can manually save on the tab that still has the wrinklers, and repeat the process.


Icon Name Description ID
SkullCookieNew Spooky cookies [note 1] Unlock every Halloween-themed cookie.
Owning this achievement makes Halloween-themed cookies drop more frequently in future playthroughs.
  1. Despite the description, the achievement is awarded only when all the cookies are bought, rather than unlocked.


  • The Halloween Season was first confirmed on Orteil's tumblr.
  • The Ghost cookies' text references the Ghostbusters theme song.
  • The Slime cookies' text references the movie The Incredible Melting Man.
  • The Bat cookies' text references the movie Dark Knight.
  • The Eyeball cookies' text references a Friedrich Nietzsche quote.
  • The Spider cookies' text references the Spider-Man cartoon theme song, as well as containing a joke about the internet.
  • The price of the cookies being four sets of fours because in some Asian languages (e.g., Mandarin, Chinese, Japanese) the number 4 sounds like the word for death.
Cookie Clicker game mechanics
Cookies ClickingBuildings
General AchievementsCpSMilkGolden CookiesNews TickerOptionsCheatingSugar Lump
Upgrades Upgrades overview
Multipliers: Flavored CookiesKittens
Research: GrandmapocalypseWrath CookiesWrinklersShiny wrinklers
Ascension AscensionHeavenly ChipsChallenge Mode
Seasons Seasons overview
Valentine's DayBusiness DayEasterHalloweenChristmas
Minigames Minigames overview
GardenStock MarketPantheonGrimoire
Further reading Gameplay
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