>>33971593Challenge mode is available when you transfer a completed Black 2 file to another copy of B2W2. It increases the levels of trainer and gym leader pokemon and gives gym leaders + E4 an extra pokemon along with some better held items like Marshall's Conkeldurr having a Flame Orb to go with his Guts ability. It's pretty annoying to set up since you need two DS's and a postgame Black 2 file to transfer the Challenge Key, but worth a shot.
