Monkey Bastions are towers that have different purposes depending on what you set them at. There are three monkeys in charge of the Bastion, and has three upgrade paths... one for each mode. There is Garrison Mode, Defensive Mode and Offensive Mode. It costs 1200$ on Medium, has no range, but instead a range in which your monkeys can go, if they are sent to Defensive or Offensive. Garrison Mode does have a range though, so yeah. UPGRADES ONLY EFFECT THE MODE THE BASTION IS CURRENTLY IN! Killing Blow will NOT work in Defensive Mode, etc.