Demonic Consultation is a one-mana instant that searches for a named card through an unusually risky exile process. After you choose the name, it exiles the top six cards, then reveals cards until the named card appears. That card goes to your hand and the other revealed cards are exiled, making the spell extremely efficient when it succeeds and potentially devastating when it does not.
Thassa's Oracle provides a deliberate use for exiling the entire library in a deck with blue. With Oracle's entry trigger on the stack, naming a card absent from your library lets Consultation exile everything remaining. Oracle can then satisfy its win condition when its trigger resolves, provided opponents do not disrupt the relevant pieces or otherwise change the outcome.
As an ordinary tutor, the initial six-card exile is the main danger. If the only copy of your named card is among those six, the subsequent search cannot find it and continues through the library. You also lose access to other cards exiled along the way, which can remove backup plans or essential answers even when the named card is found.
Use Consultation with a clear purpose and an exact understanding of your deck. It fits compact combo strategies that intentionally exploit its exile effect more naturally than slower value decks that need their remaining library intact. Its instant speed offers flexible timing, but it does not protect the resulting sequence from countermagic or other interaction.
