Osiris
Secret · Cursed Egg · Halloween 2026
1,897
exist
- Odds
- 1 in 5,000,000
- Wiki’s average hatch
- 150 days
- Coins
- x100
- Candy Corn
- x50
Black Market row · 1,000,000,000 coins · 3% chance · cap 25
Secret pets — named since Update 5.1
Build the Pyramid! Secret Pets
The game’s V3.0 update log spends two words on this system — “Added secrets” — and Update 4.0 adds “Fixed secret pets not showing how many exist”. Update 5.1 is what turns the counter on: the studio started posting every Secret hatch to a Discord channel with a running total, and its note says the count is visible “on the wiki’s Pets page by navigating to a specific secret”. This page collects the four names, the egg each one is filed under, the odds and multipliers the owner-linked wiki prints, and the counts as they stood on October 27, 2026.
Counters and hatch feed re-read October 27, 2026 at 05:32Z UTC and again 25 minutes earlier; the wiki’s per-secret pages were read the same hour.
Four of them exist, and one of the four is a single copy
The studio’s counter listed Osiris 1,897, Dragon of Ra 667, Grim Reaper 241 and Apophis 1 — 2,806 in total across every server ever. A read 25 minutes earlier had Osiris at 1,889 and the other three identical, so the numbers move one hatch at a time.
The rarest is 1 in 50,000,000
That is the Grim Reaper, per the owner-linked wiki. The same page prints 1 in 5,000,000 for Osiris and Dragon of Ra and 1 in 25,000,000 for Apophis. None of those four figures comes from an egg panel this site has read — see the last section for what that changes.
The four, one card each
Odds, multipliers and market rows: owner-linked wiki · counts: studio counterDragon of Ra
Secret · Nile Egg
667
exist
- Odds
- 1 in 5,000,000
- Wiki’s average hatch
- 150 days
- Coins
- x75
- Candy Corn
- none printed
Black Market row · 1,000,000,000 coins · 3% chance · cap 15
Apophis
Secret · Basic Egg
1
exist
- Odds
- 1 in 25,000,000
- Wiki’s average hatch
- 752 days
- Coins
- x120
- Candy Corn
- none printed
Black Market row · 2,000,000,000 coins · 3% chance · cap 5
Grim Reaper
Secret · Cursed Egg · Halloween 2026
241
exist
- Odds
- 1 in 50,000,000
- Wiki’s average hatch
- 1,504 days
- Coins
- x200
- Candy Corn
- x90
Black Market row · 5,000,000,000 coins · 1.5% chance · cap 3
Two names are Halloween-world pets and two are not: Osiris and Grim Reaper are filed under the Cursed Egg, which charges 250 Candy Corn a hatch, while Dragon of Ra is filed under the Nile Egg (1,500 Coins) and Apophis under the Basic Egg. The Halloween world is scheduled to stay in game until November 1, 2026, in the studio’s own words in its Discord on October 19.
Where the “exist” number comes from
Two surfaces print this count, and they are the reason it can be quoted at all. One is the status endpoint the owner-linked wiki serves (build-the-pyramid.abran.dev/api/rolink/v1/state/global_stats), which returns a plain object keyed by secret name. The other is the studio’s #secret-pet-hatches channel, where each hatch is a post reading New Secret Pet Hatched! followed by the name, Total Hatched: N and the buyer.
At 05:05Z UTC the channel’s last three totals read Osiris 1,889, Grim Reaper 241 and Dragon of Ra 667; two minutes later the endpoint read 1,889 / 241 / 667. They agreed before the first post of the next Osiris hatch moved the endpoint’s number on. That agreement is what makes the cards above worth printing — a single surface would be one unverified number.
- The count is game-wide and permanent. It is not the number for sale, and it is not what you own.
- Eight Osiris hatches printed in the feed inside one 26-minute window, and the counter moved by eight across the 25 minutes between the two reads here. Treat the numbers as a snapshot with a time on it.
- Apophis read 1 in both reads taken today. One copy in the world is why its card is worth reading even if you never see one.
What 1 in 50,000,000 actually means
The wiki also prints an average hatch time beside each secret: 150 days for Osiris and Dragon of Ra, 752 for Apophis, 1,504 for Grim Reaper. Those are not measured averages; they are the odds divided by one fixed hatch rate. Divide each odds by 33,245 hatches a day and the wiki’s column comes out exactly: 5,000,000 ÷ 33,245 = 150 days; 25,000,000 ÷ 33,245 = 752; 50,000,000 ÷ 33,245 = 1,504.
So the column assumes you hatch an egg every 2.6 seconds around the clock, which is what an auto-hatch loop does. Slow that loop down and the wait stretches in proportion: at one hatch every 5 seconds, a 1-in-50,000,000 roll is about 2,894 days of uninterrupted hatching. This is why the players who own one pair the egg with hatch speed and luck rather than grinding it by hand.
None of the four odds includes a luck multiplier. Whether a Luck Potion or a hatch-luck pet moves a secret’s chance is not stated on any surface read for this page, so the arithmetic above is the bare number.
The other way in: the Black Market shelf
Each secret also has a Black Market row. The wiki prints a price, a chance figure and a per-restock cap, and those are on the cards above: Grim Reaper is the tightest at 3 copies, and it is the only one whose chance column reads 1.5% — the other three read 3%. The caps are the whole shelf’s stock, not a personal purchase limit — the restock post the site read on October 25, 2026 listed Skeleton Camel at a cap of 10,000 and had sold 9,398 of it.
Update 5.1 closed one door and Update 5.2 locked another: Robux purchases of a Secret stop once its stock is out (and copies bought that way were said not to count toward these same totals), and a sold-out Secret now stays sold out instead of returning with the next hourly restock. Both lines are on the Black Market page with the restock reads they came from.
The prices are Coins, and they run from 1,000,000,000 for Osiris and Dragon of Ra to 5,000,000,000 for the Grim Reaper. Earning that is a different page’s problem; the point here is that one purchase moves the global count by one, so the shelf and the counter track the same thing.
What this page does not claim
- That an egg panel prints these odds. The Cursed Egg popup read on October 17, 2026 printed six chance labels, and the smallest was 0.0008% — 1 in 125,000. A 1-in-50,000,000 figure is far past that, so the secret roll is not one of the six slots as far as this site has read. The four odds here come from the owner-linked wiki’s per-pet pages.
- Which egg a secret drops from, beyond the wiki’s filing. Only the Grim Reaper has a second read behind it: a recording published October 26, 2026 shows it in the player’s own pet list in the Halloween world. The other three rest on the wiki’s entry.
- That Apophis really comes from the Basic Egg. That is how the wiki files it, and no frame read here shows the hatch.
- Whether secrets can be traded, or what happens to Halloween-world secrets after November 1. No surface read here answers either, and the studio’s end-date line says only that the world stays until then.
- What the multipliers are worth in Coins per second. The cards print the multipliers the wiki lists; the game’s own pet window shows a multiplier on each card and this site has not measured a secret’s contribution in a session.
Secret pet questions
How many secret pets are there?
Four in the counter: Osiris, Dragon of Ra, Grim Reaper and Apophis. The studio’s hatch channel had posted only those four names at the October 27, 2026 read.
What is the rarest pet in Build the Pyramid?
The Grim Reaper at 1 in 50,000,000, per the owner-linked wiki — and the counter backs the ranking up: 241 of them exist against 1,897 Osiris at 1 in 5,000,000.
Do secrets come out of the Cursed Egg?
Osiris and Grim Reaper are filed there, in the Halloween world. The egg popup prints six ordinary chance labels, so a secret is not simply the bottom slot you can see; treat the wiki’s filing as the source and read your own hatch feed.
How long would hatching a Grim Reaper take?
The wiki’s own figure is 1,504 days at one hatch every 2.6 seconds, around the clock. At one hatch every 5 seconds it is closer to 2,894 days. Luck effects on secret odds are not documented anywhere this site has read.
Can I buy one instead?
Only while its Black Market row still has stock — 25 copies of Osiris, 15 of Dragon of Ra, 5 of Apophis and 3 of Grim Reaper per restock at the wiki’s caps. Once a row empties it stays empty, so waiting for the next hour does not bring a Secret back.