Mary Marvel #7 (1946)

Mary chases someone who has stolen plans for an invention to the waterfront. She transforms back so the villain will not run away when seeing her, thinking she can pretend to be a kid looking round the boats, but is gagged from behind and tied up by the hag, who reveals herself as Georgia Sivana, and shows she has stolen a bullet deflector. She takes Mary in a boat, ties an anchor to her neck, and throws her into the water, where the ropes become tighter due to the water. Mary starts falling unconscious, but is saved by mermaids who place her in an air tank, and she meets Father Neptune, King of the seas. But she thinks it is a dream and she is in the last few seconds of life. The castle is suddenly attacked by a group of fish-like pirates riding on giant lobsters, led by Black Barnacle. Mary transforms and is able to stop the pirates, but Black Barnacle sprays black ink at her allowing him to escape. Though Mary thinks it is a dream, she decides to go after him anyway. She defeats his trained giant octopus and his sharks, and brings him and his crew back captives. She is given a Jeweled Ornament to wear in her hair, but turns back due to underwater lightning, caused when clouds of warm water hit clouds of warm water. She wakes up due to two fishermen, who say they caught her in their nets. Thinking Father Neptune was a dream, she transforms and defeats Georgia Sivana. However she sees the ornament in her hair later that day and realizes Neptune was not a dream.