Boulder

The Boulder is the first defense-oriented tower you get. It has a lot of health but doesn't do anything else unupgraded.

Stats
The base tower costs $385 on easy, $450 on medium, $490 on hard, $540 on insane, and $630 on impoppable. It cannot attack without late upgrades, but it's worth using.

Harder Stone
Increases the health of the boulder.

The increase is decent enough to warrant buying.

Even Harder Stone
Advances in stone-age technology make the boulder even tougher!

A very important upgrade to get, for sure.

Steel Casing
Plating the boulder in solid steel increases its health and gives it some armor!

A substantial health increase combined with the addition of 1 point of armor.

Mithril Casing
Mythical material + boulder = win.

EVEN MORE HEALTH. Also, one more point of armor.

Invincible Boulder
Boulder has absurd amounts of health.

Combined with the 2 points of armor, a boulder with this upgrade is unlikely to ever get low on health.

Table
WIP

Attack Magnet
Draws in bloon's attacks towards itself.

Very vital if you want it to perform its intended function efficiently.

Auto Regen
''Simple nanobots give the boulder a mild ability to regenerate health. Does not grant the ability to other towers.''

Regeneration is 0.5% of its health per second.

Rapid Regen
Enhancements to the nanobots doubles the rate of regeneration.

Regeneration is 1% of its health per second.

Earthquake
Boulder is so awesome it makes bloon-popping quakes.

Quakes have very short range but pop 1 layer off of all bloon kinds. Ceramics take 2 layers of damage.

Megaquake
Quakes become too awesome.

Slight range boost, pops 3 layers off of all bloon kinds. Ceramics are popped instantly.

Table
WIP