Props to our pals at Bloody Disgusting for this sweet find: during the shooting of the Universal monster classic Creature from the Black Lagoon in 1953, LIFE Magazine sent a photographer to snap a series of promotional images featuring the Gill Man in various threatening poses, including the iconic image of the Creature and his lovely co-star Julia Adams.
Color-corrected by Kerry Gammill, these incredible photos reveal the details of the monster costume in action (most likely, it's Ben Chapman in the suit here, whereas Ricou Browning wore it for the underwater scenes).
You can see the complete set of large images at Gammill's site Gammillustrations (also the home of Monster Kid magazine), along with a link to the unaltered originals.