Bloons

Bloons are the bad guys of Bloons TD. They are balloons that float on the track. They try to get to the exit of the map. They can be popped by various towers. Of course, there are also some that can only be popped by certain towers. For instance, the Lead Bloon can only be popped by the Cannon, Mortar, Boomerang Thrower (provided it is upgraded to Red Hot 'Rangs), Dart Monkey (provided it is upgraded to Juggernaut or has the 'Splodey Darts Premium Booster Upgrade) Super Monkey (provided that it is upgraded to x/3 or 2/x) and Dartling Gun (provided it is upgraded to Ray of Doom or Depleted Bloontonium Darts).

Airships
Airships are those nasty boss bloons that take multiple hits to pop and reveal some high ranking bloons. The current Airships are the M.O.A.B., the B.F.B., the Z.O.M.G. and the D.D.T..