Text (SK+errata): 1/1, Flying. ; Whenever the fourth spell of a turn is cast, flip ~this~. [Oracle 2009/07/08]
The game looks back in time to count spells played that turn. So if this card is the third played in the turn, then when you play one more there will have been four and it will trigger. It cannot, however, trigger on itself being the fourth since it will not be in play at the time that spell is played. [D'Angelo 2007/09/08]
