Pet
Mosasaurus
Mosasaurus is a 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 | ~17M–18M |
| Zone guardian | T-Rex |
| Wiki data as of | 2026-09-04 |
Mosasaurus hatches from the Mosasaurus Egg, a Eternal-rarity egg found in the Prehistoric. Prehistoric is zone 8 of 11 on the normal route; the wiki lists its entry requirement as ~17M–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.
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 2026-09-13. https://www.fandom.com/licensing
All pets: All Steal an Egg pets. Back to the Steal an Egg Hub home page.
Sukie · Editor
Sukie runs Steal an Egg Hub. Every pet, egg, zone and mutation on the site is checked against the Steal An Egg Wiki's infoboxes and the official Roblox game data before it is published, with the date it was read; anything the sources do not state is marked as not published rather than guessed.
About this site · How pages are checked · Last updated September 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.