Silcoon and Cascoon are two inherently boring Pokémon introduced in "Pokémon Ruby & Sapphire." Those games introduced more than 135 new Pokémon, many of which were designed to replace some of the more common wild Pokémon in the first two Pokémon games.
Silcoon and Cascoon are clearly derivative of two other cocoon-shaped Pokémon, Metapod and Kakuna, who are just as useless. They both evolve from from Wurmple and can't learn any moves besides "harden" until they evolve into Beautifly or Dustox.
But hey, at least Cascoon got two votes — poor Silcoon got none.