Water Mimicry – The being has a body made of water.
Hydro-Man (Marvel) is a supervillain that is more invulnerable due to being made out of water.
Electricity takes out the Hydro-Man in Occupy Avengers #2.
Chammy (Marvel) can turn into a puddle of water as demonstrated in Rocket Raccoon and Groot #10.
Naiad (DC) is a water elemental (Who’s Who in the DC Universe #2).
Weird Water Tomahawk (DC) is born in Tomahawk V1 #100.
Killian Bra’nanche – Aspen Universe – Sourcebook #1 (2016)
The Blue – Aspen Universe – Sourcebook #1 (2016)
Is Hydroman the first comic book character to demonstrate this power? Hydroman first appeared in Heroic #1 (Eastern Color, 1940).
Aballin – TSR 2145 Monstrous Compendium Annual Volume 1
Aballins – WTC11832 – Monsters of Faerun
Water Archon – D&D 4th Edition – Monster Manual 2
Water Elemental – World of Warcraft Monster Guide
Trading Card Games have beings made out of water.