If a card which is a creature only due to an effect goes to the graveyard, you can search for another copy of that card even though the card in your library won’t be a creature card.

If a copy card goes to the graveyard under this effect, you get to look for another copy of the card it was copying. This is because a copy card actually takes on the name and initial characteristics of what it copies.

Because the “search” requires you to find a card with certain characteristics, you don’t have to find the card if you don’t want to.