Falkthorne, Wrecked Voyager

When Falkthorne enters the battlefield, put the
top 4 cards of your library into the graveyard.
{t}: Return target vehicle from your graveyard to
the battlefield. Return it to your graveyard when
Falkthorne leaves the battlefield or becomes
untapped.
You may choose not to untap Falkthorne during
your untap phase.