Super Slurp Pipe
From the Super Mario Wiki
The Super Slurp Pipe is a special Warp Pipe possesed by the Koopas in The Adventures of Super Mario Bros. 3; presumably it was built by Kooky von Koopa. It is used to suck up water from an outside source into the Doomship's radiator.
In "7 Continents for 7 Koopas", the Doomship is having a radiator leak, and Cheatsy tells Bowser they need water to cool it off. As a result, he and Kooky are instructed to activate the Super Slurp Pipe. By pulling two levers, the pipe went down into the river below and sucked in a large amount of water. Princess Toadstool, who had been hiding from the Doomship in the river (along with Mario, Luigi and Toad), lost her grip to the Super Slurp Pipe's strength, and in the end, the Koopas unintentionally "Koopnapped" her.