From the Super Mario Wiki
Kinklinks are a variety of Chomps that are used to hold up chandeliers in Bowser's Keep. During the events of Super Mario RPG: Legend of the Seven Stars, Mario and Bowser fought on a pair of chandeliers, each one held up by a Kinklink. Bowser proved too difficult to defeat, so Mario (with some timely advice from Princess Peach) attacked the Kinklink holding up Bowser's chandelier instead. As a result, the Kinklink dropped the chandelier and (more importantly) the Koopa king. However, as Bowser fell, he started to throw Hammers at Mario's Kinklink. Eventually, the second Kinklink dropped Mario, sending the hero plummeting to the ground below (or so that was what Bowser planned, because Mario managed to get back up by stomping on Bowser). After the Smithy Gang took over Bowser's Keep, the Kinklinks were replaced by the Shy Guy Chandeli-Hos.
Chomp Shells, a type of weapon used by Bowser, are the shells of Kinklinks.