Whack a Bloon

 is the 57th level in Bloons 2, and the 9th level in the Rubber Jungle zone.

Solution
Pop the Monkey Ace Bloon. Now time such that the Monkey Ace such that it both pops the Spiky Bloon and the all the Camouflage Bloons in one go. Wait for the Camouflage Bloon at the top to begin decamoing while the Ace is just about to reach the "hole" of the map.