Text (LO+errata): Hideaway. ; {Tap}: Add {U} to your mana pool. ; {U},{Tap}: You may play the exiled card without paying its mana cost if a library has twenty or fewer cards in it. [Oracle 2009/07/08]
You play the last ability any time you could play an instant. During its resolution, you play the removed card. This is true even if the removed card is not an instant and could not normally be played at this time. [D'Angelo 2007/11/09]
