Membership: Dr. Henry Croft, Dr. Joseph Jennings, Betty Dean Prentiss

Purpose: Initially part of a group designed to continue life on Earth under the sea

Affiliations: Dr. Doom, Inhumans, Mr. Fantastic, Nadar and other Inhuman scientists, Namor the Sub-Mariner, Namorita, Tamara Rahn, Thing

Enemies: Attuma, Dr. Dorcas, Dr. Hydro, Maelstrom, Phaeder, Tiger Shark;
briefly the slave-collar controlled Avengers

Aliases: Amphibians of Hydrobase

Base of Operations: Formerly Hydrobase, a floating artificial island in the Atlantic Ocean, outside the U. S. Territorial waters

First Appearance: Sub-Mariner I#61 (May, 1973)

(Sub-Mariner I#61 (fb) - BTS) - Dr. Herman Frayne was once a normal man--a student and teacher of ecology. Somehow, he got the idea that the only way for man to survive was to return to the sea.

(Marvel Two-In-One#72 (fb) - BTS) - Frayne was supplied with a compound derived from the Terrigen Mist (the compound responsible for the mutation of the Inhumans) by Maelstrom and Phaeder. Frayne used this compound to mutate himself into an amphibian, took the name Dr. Hydro, began the construction of Hydrobase, and hired a number of agents to assist/serve him.

(Sub-Mariner I#61 (fb) - BTS) - Dr. Hydro initially dreamed of building a city beneath the waves, but later decided it would be easier to take Atlantis for himself. Dr. Hydro's men began hijacking airplanes and forcing them to land on Hydrobase. Once there, the passengers were taken into a chamber, where Hydro exposed them to the Terrigen derivative, mutating them into amphibians as well. Many of these people, seeing the futility in returning to the surface world, apparently joined Hydro's mission.

(Sub-Mariner I#61) - Hydro's agent Gremlin hijacked a flight carrying Namorita and Betty Dean Prentiss. The passengers were taken to Hydrobase and mutated into amphibians. Namorita was unaffected. Namor learned of the hijacking and followed another plane, captured by Lazard, to Hydrobase. However, Namor had dried out significantly from the flight and was captured by Dr. Hydro and his agents.

(Sub-Mariner I#62) - Hydro's men attacked Atlantis, their advanced training allowing them to overwhelm the Atlanteans. Namorita broke out of her containment while the others completed the Terrigenesis and she managed to free Namor. Tamara rallied the Atlanteans to fight back against their attackers, and when Namor and Namorita returned soon after, Hydro and his forces fell. Dr. Hydro himself was crushed by a damaged ship, but before he died he told Namor that there was no cure for the people who had been transformed into Atlanteans.

(Sub-Mariner I#64 (fb) - BTS) - The Atlanteans placed the Hydro-Men in a prison camp.

(Sub-Mariner I#64) - Namor was enraged to see the amphibians in a prison camp, and he tore its fences down, allowing the amphibians to wander freely throughout Atlantis. Most of the amphibians remained in a state of shock from the recent events.

(Sub-Mariner I#68) - While the Atlateans were rendered comatose by nerve gas released during the preceding fight with Virago, Namor, Namorita, Tamara, and the Hydro-Men were all spared. Croft introduced himself and Jennings to Namor, offering to help revive the Atlanteans. When they expressed concerns about manipulating chemicals undersea, Namorita suggested they all relocate to Hydrobase. Croft also suggested a force field be placed around Atlantis to shield the Atlanteans from exposure to further toxins which might complicate things. Croft sent Namor to gain force field information from Damon Walthers at Empire State University, leading to a confrontation with Force.

(Sub-Mariner I#69) - Croft used Walthers' device to build the force field around Atlantis.

(Sub-Mariner I#70) - When a frustrated Namor chastised Croft for not having succeeded at curing the Atlanteans, Croft mentioned his previous nerve toxin research. As Betty Dean watched from a distance, Namor headed off to investigate, finding instead the Piranha and the Men-Fish.

(Super-Villain Team-Up#1 (fb)) - During a testing of radioactive materials for use to save/revive the Atlanteans, Jennings wore a radiation suit and followed Croft's instructions. At that time Tiger Shark, Attuma, and Dr. Dorcas launched an assault on Hydrobase. Dorcas' Octo-Meks unleashed ionic ray attacks that knocked everyone out. Only Jennings was spared, protected by the radiation suit. Jennings activated Hydrobase's defense mechanisms.

(Super-Villain Team-Up#1) - Namor was shocked by one of Hydrobase's defense devices, but then learned of the assault from Jennings. Tiger Shark, Attuma, and Dr. Dorcas then ambushed Jennings and Namor, who fought back fiercely, but was eventually overwhelmed.

(Super-Villain Team-Up#2 (fb) - BTS) - Having recovered, Betty Dean Prentiss slipped away unnoticed from the site in which the amphibian scientists were held.

(Super-Villain Team-Up#2) - Jennings, having fled while the others battled Namor, punched out Saru-San to prevent him for calling out an alarm against him. Betty Dean watched as Dr. Doom--who at the time sought an alliance with Namor--arrived and battled some Octo-Meks. Dr. Doom found Betty and joined forces with her to locate Namor, but Betty leapt in the path of an energy blast fired by Dorcas, intended for Namor.

(Super-Villain Team-Up#3) - Namor located and freed the amphibians, and Dr. Jennings helped take away Attuma and Tiger Shark after they were defeated by Doom and Namor.

(Super-Villain Team-Up#7) - The Fantastic Four arrived on Hydrobase, warning them of the dangers of working with Dr. Doom. When Doom was injured in a struggle with the Shroud, he was found and recovered by Namorita, Tamara, and one of the amphibians (Jennings?).

(Super-Villain Team-Up#8) - While Namorita and Tamara pressured Doom to tell them where they might find Namor, Doom told them that he could return the amphibians to normal. In Hydrobase, Doom met Croft and examined their equipment, but secretly made contact with his agent, Boris.

(Super-Villain Team-Up#9) - The Avengers, defeated and forced to wear slave collars by Attuma, assaulted Hydrobase, battling Doom, Namorita, Tamara, and the amphibians.

(Avengers I#155) - The struggle continued, with the residents of Hydrobase defeating the enslaved Avengers.

(Avengers I#156) - Doom instructed the amphibians to remove the slave collars from the Avengers, who, with Namor, defeated Attuma and his agents, and also stopped Doom from claiming a cell-stimulator device.

(Ms. Marvel#15) - Tiger Shark broke free from his cell on Hydrobase, overpowering several amphibians in the process.

(Marvel Two-In-One#64) - Henry Croft sought assistance from Reed Richards, who saw a resemblance in his appearance to that of the Inhuman Triton. Reed's testing confirmed the involvement of Terrigen, and he arranged for the Thing to take Croft to Triton. Along the way the encountered a collapsing Roxxon oil rig, drawing them into a plot of the Serpent Squad (Anaconda, Black Mamba, Death Adder, and Sidewinder) involving the Serpent Crown. Croft stayed inside their transport craft while the Thing and Stingray investigated.

(Marvel Two-In-One#65) - Croft continued to hide out some distance from the Roxxon oil rig, and he used the ship to send a distress signal, which was picked up by Triton. Croft watched helplessly as the Serpent Squad escaped with the Serpent Crown.

(Marvel Two-In-One#66) - Croft accompanied Triton to Attilan while the Thing and Stingray went after the Serpent Squad.

(Marvel Two-In-One#71) - Reed Richards, working with Nadar and other Inhuman scientists, studied Croft and developed an anti-Terrigen compound, curing Croft. They brought the treatment chamber to Hydrobase and began to cure the other amphibians, but the compound was stolen by Helio, an agent of Maelstrom, who wished to use it to remove the powers of all of the Inhumans.

(Marvel Two-In-One#72) - The Thing and the Inhumans retrieved the compound.

(Marvel Two-In-One#72 - BTS) - The anti-Terrigen compound was used to cure the remaining amphibians.

COMMENTS: Created by Steve Gerber, Bill Everett, Mortimer, and Jim Moony.

    The name Hydro-Men comes from the OHotMU I appendix edition, but most of the indexes called them the Amphibians of Hydrobase.

    Betty Dean Prentiss is way beyond the scope of this profile, and will get her own profile eventually.


Dr. Henry Croft


    Ph.D in biochemistry and was a professor at Empire State University. Sometime after World War II (possibly topical), he and some other scientists searched for a cure to a government sponsored germ warfare project. They perfected a nerve toxin that transformed animal test subjects into monstrous, uncontrollable forms, as well as an antidote, which returned it to normal. The US government suppressed knowledge of this project, shutting it down, and they sent both the toxin and the antidote aboard one of the test ships heading towards the Bikini Islands, where it was sunk by a nuclear bomb test. These chemicals went on to mutate the Piranha and the Men-Fish.

    Croft was later consulted during the events of Atlantis Attacks, when he speculated that the Atlanteans and Lemurians must have had some sort of "ace in the hole" or they never would have challenged the USA with their much smaller numbers. He further speculated that the "Gore" person (Ghaur) likely had something to do with it.

--(seen and identified) Sub-Mariner I#68 (70(fb), 68-70, Super-Villain Team-Up#1(fb), 8, Marvel Two-In-One#64-66, 71, [Marvel: The Year in Review 1989]




Sub-Mariner I#61, p17, pan1 (main)
Sub-Mariner I#68, p15, pan10 (Dr. Henry Croft)

Sub-Mariner#61 (May, 1973) - Bill Everett & Steve Gerber (writers), Bill Everett & Win Mortimer (pencils), Bill Everett & Jim Mooney (inks), Roy Thomas (editor)
Sub-Mariner#62 (June, 1973) - Steve Gerber (writer), Sam Kweskin (pencils), Frank Garcia (inks), Roy Thomas (editor)
Sub-Mariner#64 (August, 1973) - Steve Gerber (writer), Don Heck (pencils), Don Perlin (inks), Roy Thomas (editor)
Sub-Mariner#68-70 (January-May, 1974) - Steve Gerber (writer), Don Heck (#68) & George Tuska (#69-70) (pencils), Jim Mooney (#68) & Vincent Colletta (#69-70) (inks), Roy Thomas (editor)
Super-Villain Team-Up#1 (August, 1975) - Tony Isabella (writer), Bill Everett, George Tuska & George Evans (pencils), Fred Kida & Frank Springer (inks), Len Wein (editor)
Super-Villain Team-Up#2 (October, 1975) - Tony Isabella (writer), Sal Buscema (pencils), Fred Kida (inks), Len Wein (editor)
Super-Villain Team-Up#3 (December, 1975) - Jim Shooter (writer), George Evans (pencils), Jack Abel (inks), Marv Wolfman (editor)
Super-Villain Team-Up#7 (August, 1976) - Steve Englehart (writer), Herb Trimpe (pencils), Pablo Marcos (inks), Marv Wolfman (editor)
Super-Villain Team-Up#8 (November, 1976) - Steve Englehart (writer), Keith Giffen (pencils), Owen McCarron (inks), Archie Goodwin (editor)
Super-Villain Team-Up#9 (December, 1976) - Bill Mantlo (writer), Bob Hall (pencils), Don Perlin (inks), Archie Goodwin (editor)
Avengers I#155 (January, 1977) - Gerry Conway (writer), George Perez (pencils), Pablo Marcos (inks), Gerry Conway (editor)
Avengers I#156 (February, 1977) - Gerry Conway & Jim Shooter (writer), Sal Buscema (pencils), Pablo Marcos (inks), Archie Goodwin (editor)
Ms. Marvel#15 (March, 1978) - Chris Claremont (writer), Jim Mooney (pencils), Tony DeZuniga (inks), Archie Goodwin (editor)
Marvel Two-In-One#64-66 (June-August, 1980) - Mark Gruenwald & Ralph Macchio (writer), George Perez (#64-65) & Jerry Bingham (#66) (pencils), Gene Day (inks), Jim Salicrup (editor)
Marvel Two-In-One#71-72 (January-February, 1981) - Mark Gruenwald & Ralph Macchio (writer), Ron Wilson (pencils), Gene Day (inks), Jim Salicrup (editor)

First Posted: 03/22/2004
Last updated: 09/18/2021

Any Additions/Corrections? please let me know.

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