Easter season

File:Starspawn.png

Easter is a seasonal event in Cookie Clicker. It was added on May 18, 2014, with the 1.0464 update. Since the 1.0466 update, Easter starts automatically and lasts from 7 days before Easter (Palm Sunday) to Easter itself (Resurrection Sunday)(The Saturday before Palm Sunday to Easter itself on a leap year).

After purchasing the heavenly upgrade Season Switcher, Easter can also be activated for 24 hours by purchasing Bunny biscuit. The upgrade is repeatable, but it gets more expensive each time it is bought, similar to buildings.

Upgrades

Here is a list of the 20 Upgrades that are from the Easter Season. All upgrades are egg/larvae based in theme and can be unlocked randomly when clicking a Golden Cookie, Wrath Cookie, or popping a wrinkler. The price of purchasing each egg goes up based on the number of eggs purchased so far (E in the chart below).

Easter Egg upgrades 

Icon	Name	Unlock condition	Base price	Description	ID
	Chicken egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "The egg. The egg came first. Get over it."	210
	Duck egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "Then he waddled away."	211
	Turkey egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "These hatch into strange, hand-shaped creatures."	212
	Quail egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "These eggs are positively tiny. I mean look at them. How does this happen? Whose idea was that?"	213
	Robin egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "Holy azure-hued shelled embryos!"	214
	Ostrich egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "One of the largest eggs in the world. More like ostrouch, am I right? Guys?"	215
	Cassowary egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "The cassowary is taller than you, possesses murderous claws and can easily outrun you. You'd do well to be casso-wary of them."	216
	Salmon roe	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "Do the impossible, see the invisible. Roe roe, fight the power?"	217
	Frogspawn	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "I was going to make a pun about how these "toadally look like eyeballs", but froget it."	218
	Shark egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "HELLO IS THIS FOOD? LET ME TELL YOU ABOUT FOOD. WHY DO I KEEP EATING MY FRIENDS"	219
	Turtle egg	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "Turtles, right? Hatch from shells. Grow into shells. What's up with that? Now for my skit about airplane food."	220
	Ant larva	"Common" egg (see Probabilities)	999 x 2E	Cookie production multiplier +1%. Cost scales with how many eggs you own. "These are a delicacy in some countries, I swear. You will let these invade your digestive tract, and you will derive great pleasure from it. And all will be well"	221
	Golden goose egg	"Rare" egg (see Probabilities)	999 x 3E	Golden cookies appear 5% more often. Cost scales with how many eggs you own. "The sole vestige of a tragic tale involving misguided investments."	222
	Faberge egg	"Rare" egg (see Probabilities)	999 x 3E	All buildings and upgrades are 1% cheaper. Cost scales with how many eggs you own. "This outrageous egg is definitely fab."	223
	Wrinklerspawn	"Rare" egg (see Probabilities)	999 x 3E	Wrinklers explode into 5% more cookies. Cost scales with how many eggs you own. "Look at this little guy! It's going to be a big boy someday! Yes it is!"	224
	Cookie egg	"Rare" egg (see Probabilities)	999 x 3E	Clicking is 10% more powerful. Cost scales with how many eggs you own. "The shell appears to be chipped. I wonder what's inside this one!"	225
	Omelette	"Rare" egg (see Probabilities)	999 x 3E	Other eggs appear 10% more frequently. Cost scales with how many eggs you own. "Fromage not included."	226
	Chocolate egg	"Rare" egg (see Probabilities)	999 x 3E	Contains a lot of cookies. Cost scales with how many eggs you own. "Laid by the elusive cocoa bird. There's a surprise inside!"	227
	Century egg	"Rare" egg (see Probabilities)	999 x 3E	You continually gain more CpS the longer you've played in the current session. Cost scales with how many eggs you own. "Actually not centuries-old. This one isn't a day over 86!"	228
	"egg"	"Rare" egg (see Probabilities)	999 x 3E	+9 CpS "hey, it's "egg""	229

Unlocking Eggs

Eggs are unlocked randomly during the Easter season by either popping wrinklers or clicking Golden/Wrath Cookies. The base fail rate to unlock an egg from a Golden/Wrath Cookie is 90% (0.9), while the base fail rate for a wrinkler is 98% (0.98). There are many modifiers that can reduce the fail rate.

Modifier	Factor
Green yeast digestives	1/1.03=0.970874
Santa's Bottomless Bag	1/1.1=0.909091
Hide & seek champion	0.7
Omelette	0.9
Starspawn	0.9
Selebrak, Spirit of Festivities	0.9/0.95/0.97 (Diamond/Ruby/Jade)
Mind Over Matter, Reality Bending, both	1/(1.25, 1.025, 1.275)=0.8, 0.98, 0.78
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 click a Golden cookie and you have Omelette, Starspawn, Santa's Bottomless Bag and Mind Over Matter, the fail rate is

$f=0.9*0.9*0.8*(1/1.1)\approx 0.589091$

You can also easily cheat when farming eggs drops (and other rare wrinkler's drops). If you pop a wrinkler and reload the page without saving, the wrinkler will come back. Therefore, you can save the game, pop your wrinklers, and if they drop nothing, reload the page. Then simply repeat until they drop something.

Egg Unlock Probabilities

When an egg is generated, there is a 10% chance for it to be a rare egg, otherwise it is a common egg.

If the generated egg has already been unlocked, then a second egg is generated. This reduces, but does not nullify, the effect the number of already unlocked eggs has on your chances of finding new eggs. Having more eggs reduces the chance of you finding other eggs quadratically.

The probabilities of generating a new egg, a common egg, any rare egg, or a specific rare egg (e.g. omelette) can be calculated using the following formulas, where n is the number of normal eggs already unlocked, and r is the number of rare eggs already unlocked:

• Pr(new egg)$=1-(\frac{6n+r}{80})^2=1-\frac{9n^2}{1600}-\frac{3nr}{1600}-\frac{r^2}{6400}$
  $=1 -0.005625 n^2-0.001875 n r-0.00015625 r^2$

Pr(new egg)

		Number of rare eggs already unlocked
		0	1	2	3	4	5	6	7	8
Number of normal eggs already unlocked	0	1.	0.999844	0.999375	0.998594	0.9975	0.996094	0.994375	0.992344	0.99
	1	0.994375	0.992344	0.99	0.987344	0.984375	0.981094	0.9775	0.973594	0.969375
	2	0.9775	0.973594	0.969375	0.964844	0.96	0.954844	0.949375	0.943594	0.9375
	3	0.949375	0.943594	0.9375	0.931094	0.924375	0.917344	0.91	0.902344	0.894375
	4	0.91	0.902344	0.894375	0.886094	0.8775	0.868594	0.859375	0.849844	0.84
	5	0.859375	0.849844	0.84	0.829844	0.819375	0.808594	0.7975	0.786094	0.774375
	6	0.7975	0.786094	0.774375	0.762344	0.75	0.737344	0.724375	0.711094	0.6975
	7	0.724375	0.711094	0.6975	0.683594	0.669375	0.654844	0.64	0.624844	0.609375
	8	0.64	0.624844	0.609375	0.593594	0.5775	0.561094	0.544375	0.527344	0.51
	9	0.544375	0.527344	0.51	0.492344	0.474375	0.456094	0.4375	0.418594	0.399375
	10	0.4375	0.418594	0.399375	0.379844	0.36	0.339844	0.319375	0.298594	0.2775
	11	0.319375	0.298594	0.2775	0.256094	0.234375	0.212344	0.19	0.167344	0.144375
	12	0.19	0.167344	0.144375	0.121094	0.0975	0.0735938	0.049375	0.0248438	0

• Pr(common)$=\frac{72-6n}{80}(1+\frac{6n+r}{80})=\frac{9}{10}-\frac{3n}{400}-\frac{9n^2}{1600}+\frac{9r}{800}-\frac{3nr}{3200}$
  $=0.9 -0.0075 n-0.005625 n^2+0.01125 r-0.0009375 n r$

Pr(common)

		Number of rare eggs already unlocked
		0	1	2	3	4	5	6	7	8
Number of normal eggs already unlocked	0	0.9	0.91125	0.9225	0.93375	0.945	0.95625	0.9675	0.97875	0.99
	1	0.886875	0.897187	0.9075	0.917812	0.928125	0.938437	0.94875	0.959062	0.969375
	2	0.8625	0.871875	0.88125	0.890625	0.9	0.909375	0.91875	0.928125	0.9375
	3	0.826875	0.835313	0.84375	0.852188	0.860625	0.869063	0.8775	0.885938	0.894375
	4	0.78	0.7875	0.795	0.8025	0.81	0.8175	0.825	0.8325	0.84
	5	0.721875	0.728438	0.735	0.741563	0.748125	0.754688	0.76125	0.767813	0.774375
	6	0.6525	0.658125	0.66375	0.669375	0.675	0.680625	0.68625	0.691875	0.6975
	7	0.571875	0.576563	0.58125	0.585938	0.590625	0.595313	0.6	0.604688	0.609375
	8	0.48	0.48375	0.4875	0.49125	0.495	0.49875	0.5025	0.50625	0.51
	9	0.376875	0.379688	0.3825	0.385313	0.388125	0.390938	0.39375	0.396563	0.399375
	10	0.2625	0.264375	0.26625	0.268125	0.27	0.271875	0.27375	0.275625	0.2775
	11	0.136875	0.137812	0.13875	0.139688	0.140625	0.141562	0.1425	0.143438	0.144375

• Pr(any rare)$=\frac{8-r}{80}(1+\frac{6n+r}{80})=\frac{1}{10}+\frac{3n}{400}-\frac{9r}{800}-\frac{3nr}{3200}-\frac{r^2}{6400}$
  $=0.1 +0.0075 n-0.01125 r-0.0009375 n r-0.00015625 r^2$

Pr(any rare)

		Number of rare eggs already unlocked
		0	1	2	3	4	5	6	7
Number of normal eggs already unlocked	0	0.1	0.0885938	0.076875	0.0648438	0.0525	0.0398438	0.026875	0.0135938
	1	0.1075	0.0951563	0.0825	0.0695313	0.05625	0.0426563	0.02875	0.0145313
	2	0.115	0.101719	0.088125	0.0742188	0.06	0.0454688	0.030625	0.0154688
	3	0.1225	0.108281	0.09375	0.0789063	0.06375	0.0482813	0.0325	0.0164063
	4	0.13	0.114844	0.099375	0.0835938	0.0675	0.0510938	0.034375	0.0173438
	5	0.1375	0.121406	0.105	0.0882813	0.07125	0.0539063	0.03625	0.0182813
	6	0.145	0.127969	0.110625	0.0929688	0.075	0.0567188	0.038125	0.0192188
	7	0.1525	0.134531	0.11625	0.0976563	0.07875	0.0595313	0.04	0.0201563
	8	0.16	0.141094	0.121875	0.102344	0.0825	0.0623438	0.041875	0.0210938
	9	0.1675	0.147656	0.1275	0.107031	0.08625	0.0651563	0.04375	0.0220313
	10	0.175	0.154219	0.133125	0.111719	0.09	0.0679688	0.045625	0.0229688
	11	0.1825	0.160781	0.13875	0.116406	0.09375	0.0707813	0.0475	0.0239063
	12	0.19	0.167344	0.144375	0.121094	0.0975	0.0735938	0.049375	0.0248438

• Pr(given rare)$=\frac{1}{80}(1+\frac{6n+r}{80})=0.0125 +0.0009375 n+0.00015625 r$

Pr(given rare)

		Number of rare eggs already unlocked
		0	1	2	3	4	5	6	7
Number of normal eggs already unlocked	0	0.0125	0.0126563	0.0128125	0.0129688	0.013125	0.0132813	0.0134375	0.0135938
	1	0.0134375	0.0135938	0.01375	0.0139063	0.0140625	0.0142188	0.014375	0.0145313
	2	0.014375	0.0145313	0.0146875	0.0148438	0.015	0.0151563	0.0153125	0.0154688
	3	0.0153125	0.0154688	0.015625	0.0157813	0.0159375	0.0160938	0.01625	0.0164063
	4	0.01625	0.0164063	0.0165625	0.0167188	0.016875	0.0170313	0.0171875	0.0173438
	5	0.0171875	0.0173438	0.0175	0.0176563	0.0178125	0.0179688	0.018125	0.0182813
	6	0.018125	0.0182813	0.0184375	0.0185938	0.01875	0.0189063	0.0190625	0.0192188
	7	0.0190625	0.0192188	0.019375	0.0195313	0.0196875	0.0198438	0.02	0.0201563
	8	0.02	0.0201563	0.0203125	0.0204688	0.020625	0.0207813	0.0209375	0.0210938
	9	0.0209375	0.0210938	0.02125	0.0214063	0.0215625	0.0217188	0.021875	0.0220313
	10	0.021875	0.0220313	0.0221875	0.0223438	0.0225	0.0226563	0.0228125	0.0229688
	11	0.0228125	0.0229688	0.023125	0.0232813	0.0234375	0.0235938	0.02375	0.0239063
	12	0.02375	0.0239063	0.0240625	0.0242188	0.024375	0.0245313	0.0246875	0.0248438

Average Unlock Time

If we unlock easter eggs using only Golden Cookies, the average number of Golden Cookie clicks required to unlock all easter eggs can be calculated. The calculation includes the effects of unlocking the Omelette egg (whenever it spawns naturally). Therefore, please ignore omelette factor when calculate the fail rate in this section.

The result curve is very similar to Log-normal distribution. For each fail rate we may fit the probability curve to Log-normal distribution to find the parameter μ and σ. Then we can use the formula on Wikipedia to obtain the probability we want.

For example, at fail rate 0.9, if you clicked or popped 753 objects, then there is 50% chance to collect all Easter eggs.

Number of object needed to unlock all Easter Eggs

fail rate	50%	75%	95%	98%	Log-normal distribution
					μ	σ
0.98	2351	3524	6310	8066	7.7625	0.6003
0.97	1755	2515	4218	5245	7.4704	0.5330
0.96	1437	2005	3241	3967	7.2700	0.4946
0.95	1231	1691	2670	3236	7.1157	0.4706
0.94	1085	1474	2291	2759	6.9890	0.4546
0.93	973	1313	2019	2420	6.8808	0.4435
0.92	885	1188	1812	2166	6.7858	0.4356
0.91	813	1087	1649	1966	6.7009	0.4298
0.9	753	1003	1516	1804	6.6240	0.4254
0.875	637	845	1269	1506	6.4575	0.4185
0.85	554	733	1096	1299	6.3176	0.4148
0.825	491	649	968	1146	6.1965	0.4128
0.8	441	582	868	1027	6.0895	0.4116
0.75	367	485	722	854	5.9062	0.4108
0.7	315	416	619	732	5.7526	0.4106
0.6	246	324	483	571	5.5034	0.4110
0.5	201	266	396	469	5.3050	0.4113
0.3	148	196	291	345	4.9982	0.4112

Cookie Production Global Multiplier

The cookie production global multiplier that many of the eggs modify is essentially another form of cookie multiplier.

The final CpS formula is essentially: CpS * Cookie Multiplier (cookie types, Heavenly Chips, frenzy/elder frenzy bonus/clot penalties, etc.) * Global Multiplier

For example, if you have some cookie types and kitten bonuses totaling a 1000% cookie multiplier, and a base CpS of 10,000, giving you a total income of 100,000 cookies per second, and you bought two common eggs, your new total CpS would be 102,010 (10,000 * 10 * 1.01²). If you then unlocked another kitten upgrade increasing your base cookie multiplier to 1500%, your income would increase to 153,015 (10,000 * 15 * 1.01²)

Achievements

Icon	Name	Description	ID
	The hunt is on	Unlock 1 egg.	166
	Egging on	Unlock 7 eggs.	167
	Mass Easteria	Unlock 14 eggs.	168
	Hide & seek champion	Unlock all the eggs. Owning this achievement makes eggs drop more frequently in future playthroughs.	169

Note: The eggs only need to be 'found' for the achievements to be earned, they do not need to be purchased. While this may not matter since most eggs will end up being purchased, it is handy to know that you can get the achievements while saving the Chocolate Egg for later to get a larger sum of cookies from its one-time effect.

Gallery

The golden and wrath cookies' appearance during the Easter season.

This season is one of two seasons to have its own grandma form, the bunny grandma. The other is the Christmas Season.

Trivia

• The description of the upgrade "Duck Egg" is a reference to a popular YouTube video, "The Duck Song."
• The omelette's flavor text is a reference to the "omelette du fromage" episode of Dexter's Laboratory.
• The salmon roe flavor text is a reference to a song in the anime Tengen Toppa Gurren Lagann.
• The Century egg is an ingredient in Chinese cuisine, while the flavour text is a reference to the Discworld novel Interesting Times.
• The Shark egg's description is from the thoughts of sharks in one of Orteil's other games, Nested. It is possibly also a reference to the sharks from the Pixar film "Finding Nemo".
• The Bunny Grandma bears a striking resemblance to Frank, a character from the 2001 film 'Donnie Darko'.
• The robin egg's flavor text is a reference to the catchphrase of Robin from the 1960s Batman TV Series.
• The Golden Goose Egg's flavor text is a reference to Jack and the Beanstalk, as well as a related idiom: "killing the goose that laid the golden eggs."
• The Bunny biscuit text is a reference to one of the rabbit myths told in Watership down.
• The "egg" bears a strong resemblance to Yoshi's eggs from Super Mario World and a normal Pokémon egg from the game series "Pokémon". It may also be a reference to the glitch pokemon "Egg". This pattern is also similar to a default spawn egg from Minecraft.
• Orteil said that the flavor text for "egg" is neither a pun nor a reference. However, in French, "an egg" is pronounced "un œuf" which sounds exactly like "neuf" = 9.
• Mass Easteria is probably a reference to mass hysteria, also called mass psychogenic illness.
• Golden/Wrath cookies from a Cookie Storm or Cookie Chain still can unlock eggs.