Ra and Su, Azorius Twins

Flash, Cannot be countered
When this creature enters the battlefield target creature you do not control gains phasing ("During each player's untap step, before the active player untaps his or her permanents, all phased-in permanents with phasing that player controls “phase out.” Simultaneously, all phased-out permanents that had phased out under that player's control “phase in.”)
At the beginning of your end step detain target permanent you do not control.