Length of a Sea is the fourth level of Bloons Insanity. It is insanely hard, as the player must shoot at the very right spot with high power to get the angled Rubber Block. If everything goes well, the dart should bounce to the top-left one, back to the initial one, then the right-most one, then the bottom-center one, then the left-most one to get the Helium Bloon. Then, the next shot consists of a simple shot to pop the Helium Bloon at the left.