While challenging the Battle Factory in Johto's Battle Frontier, a Pokemon Trainer battles with you, and tells you (after defeating him):
You're just SHELLOS, if I say so myself.
I am Gen I & II Pkmn Trainer, so I don't really know what the characters of the new Pokemon are (for example, I would know that a Blissey would care for others). What does that Trainer mean? In other words, what does SHELLOS mean in this context?
After being defeated: