Twilight Sparkle tries to use magic to enhance Pinkie’s senses to get to the bottom of her “Pinkie Senses”, but instead accidentally amplifies her natural smell, instead of her sense of smell.
 
And to make matter’s worse, the odor is contagious.  
And it reeks.
 
But this doesn’t stop Pinkie Pie from smiling. Although unfortunately, she’s more willing to compromise with stinky friends than her friends are. Rainbow Dash, Applejack, Fluttershy and Rarity have gotten their coats permanently saturated in Pinkie’s foul odor, and they were forced into quarantine.
 
Now; Twilight tries to get to the bottom of this mess and Pinkie helps Twilight find a cure… But unfortunately for poor Twilight, Pinkie Pie still doesn’t understand personal space. So with the air polluted all over the library, Twilight may just have to endure the smelly penance she created herself.
 
Much to Twilight’s despair, she preferred the skunk spraying she got on Winter Wrap up over this… Hopefully if she can undo this spell it won’t be too late for her and her friends.