S.H.A.D.O.W.

The S.H.A.D.O.W. (or Supreme Hover and Atrocious Dictator of the Overrun Winds) is a nigh-invisible MOAB-class bloon that has 1000 HP. It moves at a speed between the yellow and the green bloon. Everything that is not light-based passes through this blimp, making it quite dangerous if you don't have the appropriate army. These start to appear at round 80 but take no lives after escaping if Shadow World is not active. And these are its abilities:
 * Dark Spawn: Spawns 5 Dark Bloons in random places of the screen.
 * Solidify: Becomes solid, now looking like a D.M.O.A.B. and having 3000 HP, and losing every immunity! It will then release parts of its body in random directions that deal 5 HP damage until no parts are left, which will make it go back to its shadow form. If you destroy it during this form, it can never solidify again.
 * Shadow World: If the S.H.A.D.O.W. escapes, the screen will become black and white, and 1 S.H.A.D.O.W. will appear at the start. Note that during the Shadow World the S.H.A.D.O.W. does take lives away!