Delay Spell( Tome and Blood: A Guidebook to Wizards and Sorcerers, p. 39)
You can cast spells that take effect after a short delay of your choosing.
Any other metamagic feat,
A delayed spell doesn't activate until 1 to 5 rounds after you finish casting it. You determine the delay when casting the spell, and it cannot be changed once set. The spell activates just before your turn on the round you designate. Only area, personal, and touch spells may be affected by this feat. Any decisions you would make about the spell, including attack rolls, designating targets, or determining or shaping an area, are decided when the spell is cast. Any effects resolved by those affected by the spell, including saving throws, are decided when the spell triggers. If conditions change between casting and effect in such a fashion as to make the spell impossible-- for example, the target you designate leaves the spell's maximum range before it goes off--the spell fails. A delayed spell may be dispelled normally during the delay, and can be detected normally in the area or on the target with spells such as detect magic. A delayed spell uses up a spell slot three levels higher than the spell's actual level.