Real Name: Dr. Joseph Jennings

Identity/Class: Human mutate

Occupation: Professor, scientist;
    former governor of Hydrobase

Group Membership: Amphibians of Hydro-Base/Hydro-Men (Dr. Henry Croft, Betty Dean Prentiss, others)

Affiliations: Avengers (Captain America/Steve Rogers, Iron Man/Tony Stark, Scarlet Witch/Wanda Maximoff, Wasp/Janet Van Dyne, Yellowjacket/Hank Pym), Gorgon (Gorgon Petragon), Karnak (Karnak Mander-Azur), Namorita (Namorita Prentiss), Stingray (Walter Newell), Sub-Mariner (Namor MacKenzie), Tamara Rahn, Triton

Enemies: Attuma, Dr. Lemuel Dorcas, Doctor Doom (Victor von Doom), Doctor Hydro (Herman Frayne), Gronk, Helio, Kor-Konn, Octo-Meks, Phobius, Saru-San, Tiger Shark (Todd Arliss)

Known Relatives: None

Aliases: None

Base of Operations: Unrevealed;
    formerly Hydro-Base;
    previously Atlantis

First Appearance: (Behind-the-Scenes, name unrevealed) Sub-Mariner I#61 (May, 1973);
    (seen, name revealed) Sub-Mariner I#68 (January, 1974)

Powers/Abilities: A talented scientist, Jennings has some knowledge of chemistry.

    While transformed into an amphibious, green-skinned human, Dr. Joseph Jennings developed the ability to breathe underwater, but he could also still breathe in air.

Height: Unrevealed; (6', by approximation)
Weight: Unrevealed; (180 lbs., by approximation)
Eyes: Brown
Hair: Brown

(Sub-Mariner I#61-62, 64 (fb) - BTS) - Dr. Hydro kidnapped an entire plane full of scientists and mutated them, giving them an amphibious appearance which allowed them to survive underwater. Among them was Dr. Joseph Jennings. After Dr. Hydro was defeated, the Hydro-Men learned that there was no known cure for their condition, and they were taken to Atlantis, where they were initially imprisoned before being provided with a camp.

(Sub-Mariner I#68) - When many Atlanteans fell unconscious due to a chemical agent in the water (after a battle with Virago), Namor, Namorita, and Tamara Rahn learned of the fate of the Hydro-Men, and they met Jennings for the first time. Jennings and other scientists agreed to help find an antidote for the chemical agent, but stated they needed a lab to work in as they didn't know how to manipulate chemicals underwater. Namor took the Hydro-Men to Hydro-Base, an island formerly used by Dr. Hydro that had full labs inside.

(Sub-Mariner I#69 (fb) ) - Jennings saw Croft and the others place a force field around Atlantis so they could work.

(Super-Villain Team-Up I#1 (fb)) - Working with radioactive materials in the experiments to save the Atlanteans, Jennings put on a radiation suit to manipulate materials, while Dr. Henry Croft gave him remote instructions. Just then, Tiger Shark, Attuma, and Dr. Lemuel Dorcas attacked Hydro-Base along with Attuma's men (including Saru-San and Kor-Konn), with Dorcas' robots, the Octo-Meks, knocking out everyone on the island with an ionic ray except for Jennings, as the suit protected him. After activating Hydro-Base's mechanical defense system, Jennings spent a few days hiding.

(Super-Villain Team-Up I#1) - Namor arrived at Hydro-Base and fought off the defense system, after which Jennings approached him, explaining what had happened. After Namor defeated Attuma's men, Jennings explained what had happened, and then Tiger Shark, Dorcas, and Attuma attacked. Working together, the villains defeated Namor.

(Super-Villain Team-Up I#2) - Jennings knocked out Saru-San so he could hide on Hydro-Base.

(Super-Villain Team-Up I#3) - Days later, Jennings saw Namor defeat the villains, and the Hydro-Men were released.

(Super-Villain Team-Up I#7 (fb) - BTS) - Jennings learned that Namor had gone missing, and he believed that Doctor Doom was behind it.

(Super-Villain Team-Up I#7) - Jennings, Tamara Rahn, and Namorita found Doctor Doom wounded and then tended to him. Doom woke up in a fury.

(Super-Villain Team-Up I#8) - As Jennings and the others confronted Doom about Namor's absence, Doom claimed that he was Namor's ally.

(Super-Villain Team-Up I#9 (fb) - BTS) - Doctor Doom claimed that he could change the Hydro-Men back to normal, so he coerced Jennings and the others into serving him for a time. When the Avengers attacked, Doom took control of the heroes with tech-collars.

(Avengers I#155) - At Doctor Doom's orders, Jennings helped restrain the Avengers. They later escaped.

(Marvel Two-in-One I#71 (fb) - BTS) - Jennings was elected the governor of Hydro-Base. Stingray came to stay on the island. Weeks later, Croft sent a communication saying he would be visiting soon.

(Marvel Two-in-One I#71) - Mr. Fantastic, Thing, Gorgon, Karnak, and Triton arrived on Hydro-Base, with a cure for the Hydro-Men having been developed. Dr. Croft revealed that he was back in human form now, and Jennings soon made the announcement to the rest of the Hydro-Men, who immediately began putting themselves in a chamber to restore themselves to human form. Helio, Gronk, and Phobius attacked, disrupting the transformations, but the heroes soon defeated them.

(Marvel Two-in-One I#72 - BTS) - The Hydro-Men were cured.

Comments: Created by Steve Gerber, Don Heck, and Jim Mooney.

    Joseph Jennings originally received a sub-profile under the Hydro-Men profile.

    This profile was completed 5/10/2021, but its publication was delayed as it was intended for the Appendix 20th anniversary 's celebratory event.

Profile by Chadman.

Dr. Joseph Jennings has no known connections to:

images: (without ads)
Marvel Two-in-One I#71, p9, pan3 (main)
Sub-Mariner I#68, p9, pan10 (face)

Sub-Mariner I#61 (May, 1973) - Bill Everett (writer/artist), Steve Gerber (writer), Win Mortimer (penciler), Jim Mooney (inker), Roy Thomas (editor)
Sub-Mariner I#62 (June, 1973) - Steve Gerber (writer), Sam Kweskin (penciler), Frank Garcia (inker), Roy Thomas (editor)
Sub-Mariner I#64 (August, 1973) - Steve Gerber (writer), Don Heck (penciler), Don Perlin (inker), Roy Thomas (editor)
Sub-Mariner I#68 (January, 1974) - Steve Gerber (writer), Don Heck (penciler), Jim Mooney (inker), Roy Thomas (editor)
Super-Villain Team-Up I#1 (August, 1975) - Tony Isabella (writer), Bill Everett, George Tuska, George Evans (pencilers), Fred Kida, Frank Springer (inkers), Len Wein (editor)
Super-Villain Team-Up I#2 (October, 1975) - Tony Isabella (writer), Sal Buscema (penciler), Fred Kida (inker), Len Wein (editor)
Super-Villain Team-Up I#3 (December, 1975) - Jim Shooter (writer), George Evans (penciler), Jack Abel (inker), Marv Wolfman (editor)
Super-Villain Team-Up I#7 (August, 1976) - Steve Englehart (writer), Herb Trimpe (penciler), Pablo Marcos (inker), Marv Wolfman (editor)
Super-Villain Team-Up I#8 (November, 1976) - Steve Englehart (writer), Keith Giffen (penciler), Owen McCarron (inker), Marv Wolfman (editor)
Super-Villain Team-Up I#9 (December, 1976) - Bill Mantlo (writer), Bob Hall (penciler), Don Hall (inker), Archie Goodwin (editor)
Avengers I#155 (January, 1977) - Gerry Conway (writer), George Perez (penciler), Don Perlin (inker), Gerry Conway (editor)
Marvel Two-in-One I#71-72 (January-February, 1981) - Mark Gruenwald, Ralph Macchio (writers), Ron Wilson (penciler), Gene Day (inker), Jim Salicrup (editor)

First Posted: 09/15/2021
Last updated: 09/14/2021

Any Additions/Corrections? please let me know.

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