Plumber's Periscope

The Plumber's Periscope is an object owned by Luigi, who seemingly brought it with him to the Mushroom Kingdom. It appears in the The Adventures of Super Mario Bros. 3.

In the episode "Recycled Koopa", after Mario, Luigi, Toad and Princess Toadstool clear out the garbage Bowser and the Koopalings dumped into Mushroom Castle, they believe the Koopas will try again, at which point Toad brings out Luigi's Plumber's Periscope in a cardboard box, which he gives to Mario to spy on the Koopalings and Bowser in order to find out. With Luigi's Plumber's Periscope, Mario manages to look into a nearby Warp Pipe and see that Bully, Kootie Pie and Big Mouth Koopa are employing Sledge Brothers to dump garbage through a Warp Pipe leading to another land. Seeing the Koopalings doing this, Mario and Luigi jump through the Warp Pipe to Bowser's Castle, planning to stop the Koopalings and their polluting.