Pet
Mosasaurus in Steal an Egg
Mosasaurus is an Eternal-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Mosasaurus Egg, with a listed base income of $180M/s.
| Rarity | Eternal |
|---|---|
| Zone | Prehistoric |
| Egg | Mosasaurus Egg |
| Income | $180M/s |
| Hatch reward | +600k Speed, $18b |
| Grow time | 6h |
| Zone speed needed | 18M |
| Zone guardian | T-Rex |
| Wiki data as of | 2026-09-04 |
Mosasaurus hatches from the Mosasaurus Egg, an Eternal-rarity egg found in the Prehistoric. Prehistoric is zone 8 of 12 on the wiki's Biomes list; the wiki lists its entry requirement as 18M speed, and the nests there are watched by the T-Rex.
The wiki lists its base income as $180M/s, which ranks it 1st of the 8 Prehistoric pets by base rate. Base rate is what a normal-size, un-mutated hatch earns; everything above that comes from the size roll and the colour mutation.
With a colour mutation and no size bonus, the same Mosasaurus would earn roughly: Silver ×1.2 ≈ $216M/s, Golden ×2.5 ≈ $450M/s, Rainbow ×3.5 ≈ $630M/s (multipliers from the wiki's Mutations page; arithmetic is ours). Add a Giant (×3) or Huge (×5) size roll on top and the numbers multiply again.
Hatching it pays a one-off reward of +600k Speed, $18b, and the egg takes 6h to grow in the pen. That reward is the reason low-income eggs are still worth stealing early: the speed bonus is what gets you into the next zone.
Eternal is rarer than Secret in practice — 1.7 % of players held the 'Hatched Eternal!' badge on 2026-09-13.
A mutated or oversized Mosasaurus earns a multiple of its $180M/s base. Pick Mosasaurus in the Steal an Egg calculator to apply the wiki's mutation and size multipliers.
Sources & further reading
Other pets
- Tralaledon
Tralaledon is a Secret-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Tralaledon Egg, with a listed base income of $32M/s.
- T-Rex
T-Rex is a Secret-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the T-Rex Egg, with a listed base income of $25M/s.
- Bronto
Bronto is a Cosmic-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Bronto Egg, with a listed base income of $1.5M/s.
- Triceratops
Triceratops is a Cosmic-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Triceratops Egg, with a listed base income of $1.2M/s.
- Ankylosaurus
Ankylosaurus is a Mythic-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Ankylosaurus Egg, with a listed base income of $120K/s.
- Pterodactyl
Pterodactyl is a Legendary-rarity pet from the Prehistoric zone in Steal an Egg, hatched from the Pterodactyl Egg, with a listed base income of $22K/s.
Pet names, rarities, zones, incomes, rewards and grow times derive from the Steal An Egg Wiki on Fandom, licensed CC BY-SA 3.0; this table is shared under the same licence. Read 2026-10-12; 19 pets added from Module:Pets/Data on 2026-10-22; Bone Emperor added from it on 2026-10-24; 67 pets added from rev 2636 on 2026-10-25. https://www.fandom.com/licensing
All pets: All Steal an Egg pets. Back to the Steal an Egg Hub home page.
Sukie · Editor
Sukie is the editor of Steal an Egg Hub and writes and edits its guides, pet tables and calculators. The work centres on turning the game's published numbers into plain answers players can check: every page names its sources and the date they were read, and anything the sources do not state is left out rather than guessed. Corrections sent through the contact page are read and acted on.
Everything Sukie has written · About this site · How pages are checked · Last updated October 12, 2026
Steal an Egg Hub is an unofficial fan site. It is not affiliated with, endorsed by or associated with the 'and Collect Rare Pets' group or Roblox Corporation. Game names, images and trademarks belong to their owners.