GhostCookieNew.png

Halloween season is a seasonal event in Cookie Clicker. It begins on the 24th of October and ends on the 31st. Alternatively, it can also be activated at any time by purchasing the "Ghostly biscuit" upgrade, which is obtained by unlocking the season switcher, a heavenly upgrade that costs 1,111 heavenly chips.

The Halloween season features seven Halloween-themed flavored cookies and changes the appearance of wrath cookies to look like frowning jack-o-lanterns. The Halloween cookies can only be obtained by popping wrinklers, meaning you must first purchase the One Mind upgrade to obtain them.

SpookyCookie.png

Upgrades

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.


Icon Name Unlock condition Base price Description ID
SkullCookieNew.png Skull cookies Minimum 5% drop chance from popping a Wrinkler during Halloween Season Money.png 444.444 billion Cookie production multiplier +2%.
"Wanna know something spooky? You've got one of these inside your head RIGHT NOW."
134
GhostCookieNew.png Ghost cookies Cookie production multiplier +2%.
"They're something strange, but they look pretty good!"
135
BatCookieNew.png Bat cookies Cookie production multiplier +2%.
"The cookies this town deserves."
136
SlimeCookieNew.png Slime cookies Cookie production multiplier +2%.
"The incredible melting cookies!"
137
PumpkinCookieNew.png Pumpkin cookies Cookie production multiplier +2%.
"Not even pumpkin-flavored. Tastes like glazing. Yeugh."
138
EyeballCookieNew.png Eyeball cookies Cookie production multiplier +2%.
"When you stare into the cookie, the cookie stares back at you."
139
SpiderCookieNew.png Spider cookies Cookie production multiplier +2%.
"You found the recipe on the web. They do whatever a cookie can."
140

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:

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:

Cookie Spawn Probabilities

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:

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:

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

Probabilities for Halloween-Themed Cookies
Cookies
Unlocked
Probability of Appearance
Formula Base
(s=0.05)
With Spooky
cookies (s=0.2)
With Santa's
bottomless bag
(s=0.1364)
With Cookies
& bag (s=0.2727)
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.

Achievements

Icon Name Description ID
SkullCookieNew.png Spooky cookies [note 1] Unlock every Halloween-themed cookie.
Owning this achievement makes Halloween-themed cookies drop more frequently in future playthroughs.
108
  1. Despite the description, the achievement is awarded only when all the cookies are bought, rather than unlocked.

Trivia

  • The Halloween Season was first confirmed on Orteil's tumblr.
  • The Halloween Season was added in version 1.039.
  • The Halloween Season at first did not account for leap years, so the event would start and end one day earlier on leap years. However, this was eventually fixed in version 2.031.
  • 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 Cookie ClickerClickingBuildings
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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