Magnetic

The Magnetic is a large but highly experimental blimp.

The blimp is incredibly weak for it's size and class, at a pitiful 1750 health but 50 AD, it also moves at a relatively decent speed however.

Attacks also have a chance to damage the engine and simular features, slowing it down further and dealing bonus damage, the armor also is very fragile so hits can decrease the AD quite easily!

But the Magnetic is equipped with a massive and incredibly powerful rail gun, it uses powerful magnets to fire huge chunks of metal and bloontonium at VERY high speeds.

(This rail gun is so massive and heavy there was simply little room for any normal type of engine nor armor.) So on top of the highly experimental rail gun, the bloons also developed a very compact and very powerful engine, along with very strong armor with little weight (however unfortunately both of those things are very fragile).

The rail-gun is fixed to the front, when it finds a target, it can stop on the spot and rotate to face the target. The railgun's magnets begin charging up and whatnot and after a fairly long time (this takes between 5-10 seconds!) (and if it somehow lasts this long) it fires a HUGE chunk of metal/bloontonium at incredible speeds, too fast to be shot down, this shot will pierce through pretty much everything and there is next to nothing that will survive a direct hit from it.

The shockwave from the resulting blast will knock the Magnetic back, and damage anything nearby.

Children
It by no means has the room for any children. But when it dies it violently explodes.