The Helix Fossil (Japanese: かいのカセキShellfish Fossil) is a Fossil introduced in Generation I that can be regenerated into Omanyte. It is the counterpart of the Dome Fossil.
From Generation IV onward, the Helix Fossil is no longer a Key Item, and is a normal item. Therefore, multiples of them can be obtained, they can be held, and sent to other players via trading.
The Helix Fossil was introduced as a Trainer card in the Pokémon Trading Card Game in the Majestic Dawn expansion, first released in the Japanese Moonlit Pursuit expansion. As a Fossil Trainer card, after being played it is put onto the Bench as a Colorless-type Basic Pokémon. When the player attaches a Water Energy from their hand to the Helix Fossil, its Poké-Body allows them to search their deck for an Omanyte that evolves from a Helix Fossil and evolve Helix Fossil into the Omantye. Afterwards, the player shuffles their deck.
During the XY Series, the Fates Collide expansion included the Item cardHelix Fossil Omanyte. It allows players to look at the bottom seven cards of their deck, reveal an Omanyte they find there, and put it onto their Bench. The other six cards are then shuffled back into the deck.
The Scarlet & Violet Series saw the release of Antique Helix Fossil in the 151 expansion. This card is similar to the original Helix Fossil, being another Fossil Trainer card. It has an Ability that blocks the opponent from playing any Stadium cards from their hand, as long as Antique Helix Fossil is in the Active Spot.
Helix Fossils are also featured on the Mysterious Fossil and Unidentified Fossil cards. They are also Fossil Trainer cards which can evolve into certain Omanyte. A Helix Fossil is also on Buried Fossil, which is a Pokémon which evolves in the same way Mysterious Fossil does.
Trivia
In the first Pokémon Red and Blue run of Twitch Plays Pokémon, the chaotic control scheme resulted in the player constantly using the Helix Fossil. This lead to jokes that the game's protagonist was constantly consulting it for advice. This resulted in memes that the player worshiped the Helix Fossil and fans referred to Omanyte as "Lord Helix".
In Pokémon Omega Ruby and Alpha Sapphire, when the language is set to French, before battle Brawly says, "J'ai découvert le secret de la vraie puissance en fixant un Nautile pendant des jours et des jours..." ("I discovered the secret of true power by staring at a Helix Fossil for days and days..."), referencing the aforementioned meme.
