The Blue Marine Zone boss is a submarine consisting of a capsule similar to the Egg Mobile. It has a protective glass cover, grey plating, two propellers on the sides with a red line on their front, two dark yellow pieces of armor on the back of the roof and a blue light on the front. It also has a harpoon gun on its underside. Color-wise it is mostly light gray with a black underside. The back of the propellers are also yellow.
Powers and abilities
Robotnik's submarine is able to fire harpoons from a launcher on its underside and is able to travel underwater using its propeller engines.
In Sonic Blast, Dr. Robotnik used this submarine to attack Sonic and Knuckles when the duo where passing through Blue Marine Zone. In spite of Robotnik's efforts though, his submarine got destroyed by the two heroes in the end.
When the player enters a wide empty arena in the underwater depths of Blue Marine Zone Act 3, Dr. Robotnik will arrive from the right side of the screen in his submarine. His submarine's bottom will then light up as the harpoon launcher puts itself into place. The harpoon launcher will then shoot a harpoon horizontally leftward before retracting back into the submarine. Robotnik will then move towards the left side of the arena and go off-screen. After that, Robotnik will reappear from the left side of the arena. He will then shoot another harpoon in the same vain (this time horizontally rightward) before moving towards the right side of the arena and going off-screen. After that, Robotnik will move from the left side of the arena to the right side, and then from the right side of the arena to the left side, going off-screen in the process when turning around. However, Robotnik will do that at a faster rate than the other two times he appeared in the arena. This makes it difficult to hit him. Robotnik will then appear from the right side of the arena and shoot his harpoon diagonally into the ground before starting the whole process over again (albeit from the opposite position each time) until he is defeated.
This boss needs to be hit eight times. However, these hits must be dealt precisely into the protective glass cover of the Blue Marine Zone boss. Trying to hit this boss vehicle from any other spot will simply bounce the player back without dealing any damage. In addition, because this boss fight occurs underwater, the player faces the additional danger of suffering an instant death from running out of oxygen. Fortunately, when Robotnik shoots his harpoons into the ground, it will release an Air Bubble for the player to inhale and extend their time limit underwater.
After being defeated, the Blue Marine Zone boss will blow up before disappearing in a flash of white, clearing the Act.