The Batmobile
Originally Batman just drove a powerful red roadster.  But in Detective 48, with the simple addition of a hood ornament, it became a unique crime fighting machine
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from "The Secret Cavern" by Bill Finger, Bob Kane, Jerry Robinson and George Roussos,  Detective 48, Feb 1941

The red car didn't last long however, and was soon replaced by an imposing, dark, blue-black bat-headed, wing-tailed battle wagon.

from "Brothers in Crime" by Bill Finger, Bob Kane, Jerry Robinson and George Roussos, Batman 5, Spring 1941