Peanut candy sent young Clementine into anaphylactic shock, a life-threatening allergic reaction usually occurring immediately after exposure to certain allergens (like bee stings, shellfish, pineapple and, yep, peanuts). The shock occurs when one's immune system reacts to the allergen so intensely that one's blood pressure drops and airway constricts. Luckily, these reactions are often resolved with epinephrine.
Janelle's headaches and seizures occurred when her body was fighting a teratoma, a tumor that contains all different types of tissues. These tumors can often contain hair, teeth, bone. But it gets even more freaky: rare teratomas also contain complex organs such as eyes, torsos, and hands. Yep, now we've lost our appetites.
Grey’s Anatomy airs Thursdays at 9 pm ET/PT on ABC.