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In the episode "Recycled Koopa", Toad, suspicious of Bowser and the Koopalings, brings out Luigi's Plumber's Periscope in a cardboard box, which he gives to Mario to spy on the Koopalings and Bowser. 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. 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.
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