When you attach a Water Energy card from your hand to Helix Fossil (excluding effects of attacks or Poké-Powers), search your deck for a card that evolves from Helix Fossil and put it onto Helix Fossil (this counts as evolving Helix Fossil). Shuffle your deck afterward.
Play Helix Fossil as if it were a Colorless Basic Pokémon. (Helix Fossil counts as a Trainer card as well, but if Helix Fossil is Knocked Out, this counts as a Knocked Out Pokémon.) Helix Fossil can't be affected by any Special Conditions and can't retreat. At any time during your turn before your attack, you may discard Helix Fossil from play. (This doesn't count as a Knocked Out Pokémon.)
