Name: A Wall Unlike Any Other
Description: Wall-breaking has become extremely easy now, but this unique wall has more to it than just good defensive stats, whether this is through strange typing, ability, or anything else to hinder the conventional methods of wall-breaking.
Okay, that's about as far as I can go without getting too specific. What I basically thought we'd need for the metagame is something very unique that puts a whole new twist on walling - what I really had in mind, before reading that specific abilities couldn't be mentioned, was a wall with either Unaware or Magic Guard, just as an example of two possibilities, not a requirement or anything. Unaware would ignore stat-boosters, making it harder to overwhelm for the common sweeper, and Magic Guard would be a protection from status, Leech Seed and entry hazards. Those are just two examples and I'm sure more could thought up. (by the way, I don't see Clefable and Bibarel as particularly viable walls)