Searches more copies of himself from the deck while in the graveyard.
Great card to use for anything that has a discard cost.
Costs you 500 LP to use his effect.
Does not do anything on his own.
Volcanic Shell is a great card to use for discard costs because after discarding him you can pay 500 LP to search more copies of himself from your deck, effectively thinning your deck while maintaining card advantage. Here is a list of cards that have need discards to activate.
While a Volcanic Shell is in your graveyard, use its effect to search out another Volcanic Shell from your deck every turn. The use card trader to return the searched Volcanic Shell to the deck and draw another card. This essentially means you get an extra draw every turn as this combo can be repeated till you deck out.