Steal an Egg · Pet
Cosmic Skeleton Boss
Cosmic Skeleton Boss is a Secret pet in Steal an Egg that earns a base $45M/s. It hatches from the Cosmic skeleton boss Egg, stolen from the nests of the Cosmic biome.
EggCosmic skeleton boss EggPet stats
Base income
$45M/s
Base weight
1,000 kg
Egg
Cosmic skeleton boss Egg
Grow time
2h 30m
Speed reward
+1.6M
Cash reward
$4.5B
Source
Cosmic
Biome nest
Rarity
Secret
Where to get Cosmic Skeleton Boss
Steal the Cosmic skeleton boss Egg from the nests of the Cosmic biome, carry it back to your pen and let it hatch.
- Speed required
- 700M
- Guardian
- Cosmic Skeleton
The guardian sleeps next to the nest; the faster you are, the easier it is to outrun it. Bigger eggs are worth more but slow you down. Eggs & guardians
Estimate based on the wiki formula
Cosmic Skeleton Boss income with mutations and size
| Mutation | 1× weight1,000 kg | 10× weight10,000 kg | 100× weight100,000 kg | 200× weight200,000 kg |
|---|---|---|---|---|
| No mutation×1 | $45M/s | $186M/s | $770M/s | $1.07B/s |
| Rainbow×3.5 | $158M/s | $652M/s | $2.7B/s | $3.73B/s |
| Parasite×3 | $135M/s | $558M/s | $2.31B/s | $3.2B/s |
| Fractured×2.75 | $124M/s | $512M/s | $2.12B/s | $2.93B/s |
| Scrambled×2.75 | $124M/s | $512M/s | $2.12B/s | $2.93B/s |
| Golden×2.5 | $113M/s | $465M/s | $1.93B/s | $2.67B/s |
| Spirit Bloom×2.5 | $113M/s | $465M/s | $1.93B/s | $2.67B/s |
| Bloom×1.25 | $56.3M/s | $233M/s | $963M/s | $1.33B/s |
| Silver×1.2 | $54M/s | $223M/s | $924M/s | $1.28B/s |
Estimate based on the wiki formula (marked beta there): income = base × (weight ÷ base weight)^(37/60) × mutation, with diminishing returns above 125× the base weight. In-game values can differ. See mutations and the income calculator.
How Cosmic Skeleton Boss compares
Neighbors by income in Cosmic (5 of 8):
Earns less
La Vacca Saturno Saturnita
$2.2M/s(÷20 vs Cosmic Skeleton Boss)
Earns more
Cosmic Dragon
$60M/s(×1.33 vs Cosmic Skeleton Boss)
Other Secret pets
Cosmic Skeleton Boss guide
The Cosmic biome is guarded by the Cosmic Skeleton, and one of its Secret eggs carries a name that echoes that guardian: the Cosmic Skeleton Boss, earning $45M/s.
Egg details
The egg (listed on the wiki as "Cosmic skeleton boss egg") spawns in Cosmic, the 9th biome, which takes 700M Speed to enter. It grows for 2h 30min and pays +1.6m Speed and $4.5b on hatch. The base weight is 1,000 kg.
The $4.5b is enough for The Freeze Treadmill (3B, +100 Speed per step) with $1.5b left over.
Skeleton Boss or Cosmic Dragon
Cosmic has two Secret pets, and the data favours each in a different way:
- Cosmic Skeleton Boss: $45M/s, 2h 30min, +1.6m Speed, $4.5b
- Cosmic Dragon: $60M/s, 3h, +1.4m Speed, $6b
The Dragon earns a third more per second, but the Skeleton Boss grows half an hour faster and actually gives more Speed per egg. If you are using Secret eggs to push toward Cherry Blossom (2.5B Speed), the Skeleton Boss is the slightly better Speed egg; for income, the Dragon wins.
Rankings
- 4th of 8 in Cosmic, counting from the highest earner
- 25th of 35 Secret pets
- 74 of the 198 pets earn more overall
The jump from La Vacca Saturno Saturnita ($2.2M/s) to this pet is about twentyfold.
Mutation and weight estimates
Using the formula the wiki documents (its calculator carries a beta label), a Golden Cosmic Skeleton Boss would make about $112M/s and a Rainbow one about $158M/s. Weight pushes further: about $186M/s at 10× base weight, $770M/s at 100× and $1.07B/s at 200×. Rainbow combined with 100× weight comes to roughly $2.7B/s.
Data sourced from the Steal an Egg Wiki (CC BY-SA) and processed automatically; last synced 2026-10-11.