Amphisbaena

 is the 50th and the final level in Bloons Insanity.

Completion
To complete this level, you need to aim for the second last Tack Bloon on the bottom. Some bloons will automatically pop for a certain amount of seconds. Next, you will receive an extra dart and a boomerang Extra Dart Bloon and a Boomerang Bloon, respectively. For the boomerang, aim for the bloons on the bottom left. Note that it would be difficult to aim correctly, so aim for the bottom right with maximum power in order to have a chance of making this strategy work. You may able to use pac-man via the Pac-Man Bloon. With the pac-man, go to the left until you pop a Tack Bloon with it. You will be able to receive an extra dart. With the extra dart, pop the bloons on the top right, which are between a pair of Rubber Blocks. You may be able to either receive an extra dart or triple darts. With either one of the darts, you can use them to break one or multiple Ceramic Blocks, then pop the Bomb Bloon.

If the strategy doesn't help, you can request a better strategy in the talk page.

Trivia

 * After completing this level, a victory screen will appear, and it would be flashing, unlike the other bloons games.