Spell Bluff
You know the principles of arcane dueling, and when fighting other spellcasters, you have learned to hide the true nature of your spells until the last possible moment.
Prerequisites: Bluff 5 ranks, Spellcraft 5 ranks.
Benefit: If another spellcaster tries to counterspell your casting, she adds +4 to her Spellcraft DC when trying to determine your spell.
Because you have studied how to mask the recognizable elements of your spellcasting, you gain a +2 bonus on your Spellcraft checks to identify and counter an opponent's spell if it is a spell you know or have in your spellbook.

Spell Bluff (Teamwork)
When your ally is in the area of effect of a harmful spell, your foes are caught off guard.
Benefit: When an ally who also has this feat fails her saving throw (including voluntarily failing the save) against a spell that would harm her with an area of effect that includes her, intelligent enemies within the spell’s area take a –2 penalty on their saving throws to resist the spell’s effects.