TV Tropes' page on B-movies has a lot of ones with weird (or comic-book style) science. "Beginning of the End" (grasshoppers eat giant irradiated vegetables, grow huge and go psycho), "Invasion of the Body Snatchers" (though Star Trek probably did that one already), "The Deadly Mantis" (giant Ice Age praying mantis gets thawed out and attacks)...also, most things Mystery Science Theater 3000 did.