Tree

''Scientists discovered that leaves somehow slow down Bloons. Weird, right?''

The Tree is a special agent that drops leaves on Bloons. It costs $80 MM. These leaves slow Bloons going under the tree by 50%. Boring, right? Well, the Tree also grows! The tree will grow 1px outward per round until it is 100 px in size. (It starts at 20 px in size). Note that M.O.A.B class Bloons, instead of being slowed, will take a route around the tree and rejoin the path at the other side.

Pro
''Pro upgrade - Dead Branches! The tree now has a 10% chance to drop a dead branch every second!'''

Dead Branches pop 6 layers of a bloon, and stun them for 1 second. These cannot effect M.O.A.B. Class Bloons.

Epic
''Epic upgrade - Whomping Willow! The tree now is a whomping willow, which targets Bloons with it's branches!''

The tree now has a mind of it's own. It whacks Bloons with it's branches, attacking four Bloons at once. These whacks do an amazing 18 layers of damage! The tree can also poke M.O.A.B. Class Bloons, although this only does 1 damage.

Trivia

 * The Whomping Willow upgrade is an obvious reference to Harry Potter.