UFO

From HGWiki

UFO = UEF + IoF (the cleric epic spell Instruments of Faith). This will usually be said by a cleric in a hell or post-hell run as a means of notifying the group to: (a) gather in a tight circle for the UEF spell; (b) ready weapons for IoF

Original use probably attributable to Rainsanctum and/or Mori.