That Time Batman Discovered Pym Particles!!

Batman has cornered a gang of ne'er-do-wells in a building where SCIENCE is taking place!

Well, of course, everyone knows that upper atmosphere gases...

MAKE YOU BIG!!! 

(BTW, did anybody else feel ripped off by the movie Big? Didn't you think it would have been far better if, instead of turning into an adult, the kid turned into a giant? Just sayin'.)

Anyway, a big-ass Batman is great for fighting crime.

But there's one tried and true method to stop him:

Throw barrels of ground pepper at him. No, really.

Still, Colossal Batman has his uses:

But it's a good thing he's a billionaire, because when it's feeding time?

Some crooks do capture him.--because giants can always be caught by normal folks, you know--but Batman really does prepare for everything!

So, if it takes truckloads to feed Mega-Batman, just how much make-up did it take to so completely disguise his huge face?!?

Anyway, it's the Silver Age, so of course Superman disguised himself to fill in for Bruce Wayne at some can't-miss function, and the gasses wore off, and it's all back to status quo in the last panel.

Oh, Kal-El, you've never been more wrong. We need more Giant Batman. More and more!!

From Detective Comics #292 (1961)