Looks like Margaret Hamilton in The Wizard of Oz

Slightly, but WAY, WAY more attractive than Margaret Hamilton.

Ms. Bialik is drop-dead, knee-quaking gorgeous, are you kidding me? A real, authentic beauty in Hollywood; a very rare thing.

You need to get a CT scan of your brain immediately

I LOVE that she never felt the need to do plastic surgery.
She is very natural and - yes I'll say it - pretty!
Of course, they dress-down her looks for BBT but she's actually nice looking.

You are ABSOLUTELY right! All the way through the movie I kept thinking of Margaret Hamilton as well – a young Margaret Hamilton, of course – I love Miss Gulch! I think it is quite brave of Miss Bialik to do the first third of the film with no make up basically. But she is such a substantial persona and so fascinating to watch, it doesn't matter.

Funny enough, Margaret Hamilton was somewhere between 36-39 when she played the Wicked Witch in the Wizard of Oz, so to say Mayim Bialik, at 39/40, looks a little like her back then isn't very far off, since they're roughly the 'same age' in those two comparisons. lol