The movie he rented was about a 'maniac' [='madman', 'lunatic'] who goes on a murderous rampage.
She drives 'like a maniac'. [=she drives in a very reckless and dangerous way]
He's a complete 'maniac' when he's playing football.
(..) But for you, I wouId shoot the Surgeon GeneraI. Mayor TiIton, may we have a word? I aIways have time for the press and my IoyaI constituents. Let me out of these cuffs, you drive Iike a maniac. Sorry, we're Iate for the baII. AIice and the rabbit'II be disappointed. Now you're being cynicaI. (..)1994 The Mask