Piplup

Piplup is one of only a handful of Pokemon in Little Cup with access to both Stealth Rock and Defog, meaning it can remove your opponent's entry hazards while setting up its own. Piplup's Water typing means it isn't weak to Stealth Rock, so it can switch in more easily than other Defoggers, especially along with its good defenses. Piplup is no slouch offensively either, as its good Special Attack stat along with a decent STAB move in Scald means it can beat common Stealth Rock users such as Drilbur and Archen. However, it has less offensive presence than these two and access to less special attacking options, which means it can sometimes become setup bait for Pokemon that are specially bulky or resist Piplup's moves. Piplup is also outclassed in other roles by Chinchou, so it can be quite predictable.