The previous Harley Quinn episode revealed the real villain of this season, and it's not Brainiac. It also introduced us to Frankette, a new baby plant born from Frank's remains and Poison Ivy's DNA.

Poison sumac is considered more allergenic than poison ivy and poison oak, which are other well-known plants in the Toxicodendron genus of the sumac family. Poison sumac releases an oil known as ...