Delayed Spell

WHen you cast this spell, choose a spell 5th level or lower. The selected spell is now ready to be cast at no action whenever you stop concentrating on this spell. 

AT HIGH LEVERS. 
WHen you cast this using a spell slot of 9th level, you may select spells up to 7th level to use with this spell, there is no limit to how long you can concentrate on this spell, and you can maintain concentration on this spell while sleeping.