Understudy. Prereq: Versatile performer. When an allied spellcaster is killed or made helpless, you may select one spell that ally knows or had prepared for the day that is at least two levels lower than you highest level spell known. Until that ally is alive and no longer helpless, or out of your sight for at least an hour, you may cast the selected spell using a spell slot two levels higher. You may only have one Understudy spell in effect at a time, selecting a new understudy spell ends your ability to cast the previous one. #Microfeats.
#Microfeats are experimental feats we have in playtesting or development (and may well change before they ever get used in a product – or may get cut entirely). Today’s microfeat is inspired by http://paizo.com/products/btpy8vi5?Ultimate-Options-Bardic-Masterpieces