A sub-tower is a tower created by another tower. Most sub-towers are temporarily created by an attack or Activated Ability from a parent tower (such as the Engineer Monkey's Sentries, which it builds with an attack that targets random positions within range) and disappear after a short time, though some last until their parent tower is sold or removed in some way, and some remain even if the parent tower is removed. Some sub-towers are selectable, allowing the player to see properties such as their range or targeting options, but not all. They do not have upgrades of their own, though some parent towers have upgrades that affect sub-towers (such as the Engineer Monkey's Sprockets). Most sub-towers have mechanics that interact with their parent towers, such as attacking sub-towers adding the damage they deal to the damage counts of their parent towers in addition to their own.
