the toxic swamp is 4 place you go during the campaign, There you will find new character such as: Spidey, medusa, coco the troll, and the lich. the last level of the toxic swamp(4-10) is where you fight the giant wizard. The Toxic Swamp is one of the places you can unlock the most characters. When your playing the Toxic swamp you will fight all kinds of new heroes.
Toxic Swamp is where you fight snake queen, and tentacules.