Hydronoid

Hydronoids are a sapient spacefaring species of amphibious humanoids which hail from an oceanic planet.

Their technology includes means to erase and reprogram the minds of other creatures.

Biology
Hydronoids are green-skinned bipeds with a humanoid body plan and no tail. They have large glossy black eyes and short head crests.

History
A group of Hydronoids invaded Earth in the 1970s and erased the minds of several Humans, hoping to prevent humanity from colonizing space and threatening oceanic planets with pollution. They were defeated by Aquaman, Batman and Robin.