If your Animal is in your deck but you don't know where in your deck, you may search your deck to find your Animal, exile it, and then shuffle your deck.

Due to target validity, it is usually not possible to exile an Animal that is not in play. The Scarab, however, can be exiled from your deck, specifically because this is mentioned on this card.

In general, the positioning of the Scarab is known in your deck. If this is not the case, search your deck for your Scarab to exile it, then shuffle your deck.