Vortex: Deadly Master of Air

Vortex: Deadly Master of Air is an Event-only MOAB-Class Bloon found in the Vortex event in Bloons Monkey City. It has a boss health bar which increase every time it levels up after you complete a level of the event. Upon popping Vortex, you will see Vortex saying "You win... this time!" and receive the relative tier of CT Milestone worth in rewards. If you fail to pop Vortex, you will receive a message with the normal "DEFEAT!" showing, and text that says: "...But the Boss is damaged. Chase it down and try again!" Like Bloonarius, the Bloon Beacon is needed to summon the boss out of hiding.

It also appears in BTD5 Mobile during the Boss Event on Skull Peak.

Health
Health + RBE table below for the first 25 levels.

Speed
It moves at a relative speed of 0.2 of the speed of a Red Bloon.

Pulse/Shockwave
Every 7 sec, the Vortex starts a pulse in 100 px range, which stuns (depending on stun level) and slows towers in range for 6 sec.

The stun time is based depending on level and Vortex health.

The stun level is calculated like this: stunLevel = 0.2 + (0.1 * skulls destroyed) + Level * 0.02. 1 Is max and probably means that hit towers are turned down fully 6 sec and are only 1/7 as effective as if it would be not stunned.

Properties and Immunities

 * Vortex doesn't have any special physical properties except of being a MOAB-Class Bloon, so it can be hit by any tower (except ice and glue)
 * MOAB Assassins damage is reduced from 750 to 375.
 * It can be affected by the Boss Blast and Boss Chill, which cost Bloonstones. Absolute Zero and Pop and Awe also work, but only on the Mobile version.
 * You get 1.5 cash per damage on Vortex.
 * Moab Mauler does 10 bonus damage, but SHREDR Spikes does 2 instead of 4 damage.

Strategies

 * A single Super Monkey, placed near the center of the track should be able to defeat Vortex on low levels. Additional towers would be needed to avoid loss of life to any minor bloons that leak through.
 * The battle does seem to consist of multiple continuous rounds, particular as evidenced by production from Banana Farms, as well as deployment of crates.
 * Spamming and selling MOAB Assassins could be used. It becomes effective at the end to do some damage against it. With Monkey Tycoon lvl 13, you can spam them without money loss (dealing damage fill your bank again) and your damage is only depending on your speed.
 * Vortex is immune to slowing and stunning, so Sabotage Supply Lines, Cripple MOAB and Pop and Awe will not work against the blimp.
 * MOAB Maulers do deal more damage to it than Missile Launchers, so they can be of some use.
 * Many 0-0 Dartling Guns, with some lead popping power, could be a viable option, considering their quick fire rate and the ability to aim at Vortex or a large rush of bloons. Vortex's large size makes it easy to hit, even with the spread. Dartling Gun lvl 2 or above works well with this strategy.
 * 1/3 Spike Factories are very effective, and are a good supplement towards 3/0 tacks or 2/3 bombs (or sniper or dartlings).
 * A ring of fire is a good starting tower.
 * Boss Bane will instantly defeat Vortex level 1.

Trivia

 * Vortex is, after the BFB, the ZOMG and the Bloonarius the Inflator, the fourth MOAB-Class Bloon to have eye symbols.
 * It is also the only one to have more than two eye symbols.
 * Vortex is, after Bloonarius the Inflator, the second boss Bloon in BMC.
 * Vortex resembles a blue DDT or a recolored ZOMG bloon with black shark fins.
 * Vortex has a propeller in the front on its icon, but in-game, it has its propeller smaller.
 * Vortex seems to be the air-based counterpart of Blastopopoulos: Demon of the Core, since they stun Towers and share a similar structure. However, Vortex uses a pulse instead of a fireball.
 * In the Mobile version, Absolute Zero can slow Vortex when on the track, allowing towers more time to attack it.
 * Vortex is slightly larger in BMC Mobile than its flash counterpart, along with slight changes in style.
 * In BMCM, Vortex's hitbox is a circle, and can be damaged from road spikes even if he is not touching them completely.