Ditto

Ditto is a special agent that copies another tower (and all it's upgrades). it is extremely useful on Lava Bath, where most of the stage is lava. It can copy Gwendolyn (who can be placed on the lava).

Pro
Pro Ditto can copy two towers and combine their abilities similar to Monkey Fusion.

Trivia

 * This tower is obviously based off of the Pokemon Ditto