The Penguin's Submarine

The Penguin's Submarine is used by The Penguin in LEGO Batman: The Videogame but is also a unlockable vehicle in LEGO Batman 2: DC Superheroes to drive around Gotham's harbor.

LEGO Batman: The Videogame
The Penguin's Submarine first appears in the intro to the 2nd  called Power Crazed Penguin. It is seen moving under water and other villains are aboard where they are told of Penguin's evil plot. It later appears on the levels: Batboat Battle as a boss & in Harboring a Grudge as a playable vehicle. After  "Harboring a Grudge" the player will unlock his vehicle alongside Killer Croc's Swamp Rider.

Description
The submarine has a sleek design with missiles on the side allowing it to shoot projectiles and submerge and pass under barriers in the way.

LEGO Batman: The Videogame
The Submarine can only be used in the story mode and free play and cannot be unlocked as there is no free roam.

LEGO Batman 2: DC Superheroes
The Submarine can be unlocked in free roam.

Trivia

 * Penguin's Submarine in LEGO Batman 2 primarily rides over water and does not go underwater.