Monkey Satellite

The Monkey Satellite is a tower that requires the Monkey Aerospace Administration to exist, but it is well worth it. By default, all it does is target a very wide area with microwave radiation that pops one layer from bloons every 1.5 seconds. It costs $750 on Medium, and cannot be destroyed (Not even by One Nuke Wonder!), mostly because, well, it's orbiting the planet and stuff. Of course, unlike regular towers, this tower functions off of BTD4 logic - it has one upgrade path.

Intense Microwaves
Description: Microwaves deal more damage per second.

Cost: $750

It now pops two layers from bloons every 1.5 seconds.

Focused Microwaves
Description: Smaller satellite dishes enable focusing of stronger beams.

Cost: $625

It pops two layers from bloons every 0.75 seconds, but with half as large area.

Air-Ionizing Laser
Description: Extreme microwave focusing creates a weak plasma in the air, damaging bloons at a decent rate.

Cost: $2250

It pops three layers from bloons every 0.6 seconds, in the same area as the last upgrade.

Ion
Description: Ion Ability: Fires a destructive laser of pure ionized awesome upon the bloons.

Cost: $10000

It retains Air-Ionizing Laser as its passive attack. The Ion ability fires a 20 damage/second laser that moves along the path at the speed of a red bloon. Of course, as its effect is dynamic, so is its recharge. Its recharge is 1.75 times the time it takes for it to go from the start of the path to the end.

Trivia

 * The Ion ability is a reference to Lance's Limit Break in EBF3.