Right, "Meta has went out of ideas, how can a submarine be useful in a battle against floating bloons", you think? Don't worry, I've managed to work it out! The Monkey Submarine has 2 modes (shown as 2 new attack modes buttons): Submerge and Surface. While it's Submerging, projectiles can't hit it unless it's a lightning or electronic-based projectile (since seawater is very conductive). It has 2 cannons, one shoots homing darts, these darts can pierce 3 bloons each. This cannon can be used on both modes, since the homing darts will fly upward, out of the water first if it's Submerging. The second cannon however, is a frontal cannon, and acts just like a Monkey Buccaneer's cannon. This cannon can only be used while it's on Surface (if the submarine is on Surface, BOTH cannons can be used!)