Summon Whirlwind

"Whirlwind will blow bloons away from the exit, but will thaw bloons and remove glue."

- BTD4 description

Summon Whirlwind is an upgrade for the Monkey Apprentice. A Monkey Apprentice with this upgrade is called a Disciple of Air in Bloons TD 5, or a Monkey Archmage in Bloons TD 4. It allows the monkey to summon a whirlwind that can blow Bloons closer to the start.

Compared to Tempest Tornado, it attacks very few bloons, is much cheaper, and doesn't pop bloons.



Change of the Tower
The Disciple of Air in BTD5 affects the Monkey Apprentice by making it have a light blue robe and hat. It will also make it carry a wand that has a blue crystal at the end of it.

Strategies
Put Monkey Apprentices with Summon Whirlwind near the end of a track so that they're more efficient in saving players lives (putting them in the beginning won't blow the Bloons back much).

Summon Whirlwind is a key part of a cash-earning method called Regen Farming, in which players pop a Regen that is a Black Bloon, White Bloon, Zebra, Rainbow, or Ceramic, wait for it to regenerate into two of those kinds, and continue with that, earning more money. This is risky, as if too much is done, players defenses might not be able to handle it. Even more so, only having one Whirlwind Apprentice can be dangerous as it only summons a little whirlwind and takes time to regenerate. Also, this upgrade cannot push back MOAB Class Bloons, and it is effective to get more of a damage output and 2-3 Summon Whirlwind mages.

Trivia

 * Whirlwinds and Tornadoes cannot blow away Lead Bloons but the Tornadoes from Tempest Tornado Monkey Apprentices can pop Lead Bloons.
 * The Summon Whirlwind upgrade in BTD6, called "Druid of the Storm" in BTD6, is now an upgrade for the Druid instead of the Wizard Monkey (Monkey Apprentice). The same applies to Lightning Bolt, but the name of the upgrade in BTD6 is "Heart of Thunder".