Mt. Moon · Cinnabar Lab
Pokemon Yellow fossils: Helix, Dome & Old Amber
On Mt. Moon B2F you must pick Helix → Omanyte or Dome → Kabuto—one save, one shell. Separately, grab Old Amber in Pewter Museum for Aerodactyl. Revive everything at the Cinnabar Lab Fossil Room for level 30 mons (Omanyte/Kabuto evolve at 40).
Fast answer
Pick a shell, keep the amber
Helix Fossil revives to Omanyte; Dome Fossil to Kabuto. The Mt. Moon choice is permanent on that save. Old Amber → Aerodactyl does not compete with that choice—you can revive amber plus whichever shell you took. All three exit the lab at Lv.30.
Missable warning
The other Mt. Moon fossil is gone
After you take Helix or Dome, the unpicked fossil cannot be collected later on the same cartridge/save. For both Omanyte and Kabuto families you need another save, a trade partner, or transfer routes—see trade requirements and the complete Pokédex guide.
Interactive tool
Helix vs Dome decision
Tap a fossil to compare base stats (stage-1 and stage-2), see the revive target, and save your pick in this browser.
Select Helix (Omanyte line) or Dome (Kabuto line). Old Amber is handled in the next section and does not replace this choice.
| Line | Fossil | Stage 1 stats | Stage 2 | Playstyle cue |
|---|
What you receive
Revived Pokemon cards
Independent prize
Old Amber → Aerodactyl
Where to get Old Amber
After obtaining HM01 Cut, cut the tree beside Pewter Museum and enter through the side door to reach the scientist’s rear room on 1F. The paid front entrance does not lead to the Old Amber room. This does not consume your Mt. Moon fossil slot.
Why keep the amber
Rock/Flying with excellent Speed and Attack. Strong physical attacker and a natural late-game flyer once HM02 is available. Plan coverage in the Team Planner.
Cinnabar Lab
Revive walkthrough
Lab front desk and trade/metronome rooms are separate; fossil work happens in the Fossil Room. Island access ties into the main story—use the walkthrough and Secret Key notes if Cinnabar is still locked.
Team notes
Which fossil for your run?
Pick Helix / Omanyte if…
You want a Special-leaning Water/Rock wall that becomes Omastar. Strong into Fire and some physical attackers; slower than Kabutops.
Pick Dome / Kabuto if…
You want Kabutops’s Attack/Speed and Gen I Slash crits. More of a swords-dance-less physical cleaner with Water STAB later.
Always take Old Amber
Aerodactyl does not trade off against Helix/Dome. Museum visit is early; revive whenever Cinnabar is open.
Living dex both shells
Plan a second save or trade. See in-game trades and trade-to-finish for broader dex gaps.
Checklist
Fossil run tracker
FAQ
Fossil questions
Helix or Dome in Pokemon Yellow?
Helix → Omanyte/Omastar (bulkier Special/Defense). Dome → Kabuto/Kabutops (Attack/Speed + Slash). Use the decision tool above for base-stat bars.
How do I get Aerodactyl?
Old Amber in Pewter Museum, revive in Cinnabar Lab Fossil Room. Level 30 on receipt.
Do I lose Old Amber if I pick a Mt. Moon fossil?
No. Amber is a separate key item from a different location.
When can I revive?
Once you can enter Cinnabar Island’s lab Fossil Room and talk to the scientist with a fossil in the bag.
Can I get the other fossil later?
Not on the same single-player save through normal means. Trade or a second adventure is required for both shell families.
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