Historical Rules · 29 September 2017
Rule 702.74a
Official source text from the 29 September 2017 Rules release
Hideaway represents a static ability and a triggered ability. “Hideaway” means “This permanent enters the battlefield tapped” and “When this permanent enters the battlefield, look at the top four cards of your library. Exile one of them face down and put the rest on the bottom of your library in any order. The exiled card gains ‘Any player who has controlled the permanent that exiled this card may look at this card in the exile zone.’”