Koopilus

The Koopilus is King Koopa's submarine in The Super Mario Bros. Super Show! "20,000 Koopas Under the Sea / Vampire Until Ready". The Koopilus attacked Happy Harbor during the episode and Mario, Luigi and Princess Toadstool got eaten by this robotic submarine during the episode. Down there the brothers and princess were ordered by King Koopa to cut onions. Toad went inside the Koopilus and saved the brothers. At the end of the episode the Koopa submarine broke.

At the beginning of the episode Mario, Luigi, the princess, Toad and the citizens of Happy Harbor all thought that the Koopilus was a Koopa sea monster.