Lucille Austero, aka Lucille Two, is the neighbor, frenemy, and rival of Lucille Bluth.  Lucille suffers from vertigo and dates Buster briefly.  In season two, Lucille becomes the majority shareholder of the Bluth Company after the family sells off their shares.

Lucille 2 Quotes

Lucille 2: Lucille? Lucille! Aren't you something? Showing up here without your husband. Shame be damned. Caution to the wind.
Lucille: That's so sweet, darling. I'm here to support you. You're the one who's all alone and likely to stay that way. My husband's just a phone call away.
Lucille 2: That's one call per day, isn't it? Gee, I should think he'd want to save that for his lawyer.

Buster: Has your hair always been that pointy, Miss Austero?
Lucille 2: It's Lucille.
Buster: Right, right. That's my mom's name.