Sorry, I was on vacation and didn't notice this until I got back home.Physically, that resembles the umber hulk a little bit, and I believe in the 1E Monster Manual II, they were aquatic umber hulks. Are you going with that interpretation with yours, or is it just a matter of hulking monsters all looking alike to an extent?
True, I did design this vodyanoy to look slightly similar to the aquatic umber hulk, but my interpretation is closer to its Slavic roots. Here's a section of its description:
"The vodyanoy wields supernatural power over water, calling forth waves and whirlpools to trap its prey and
shrouding the surface in fog to obscure its movements. It can create illusions that confuse and deceive, mimicking the
voices of the lost and the desperate to lure victims to their doom. The souls of those it drowns are not allowed to rest but are
captured and trapped within enchanted jars hidden in its underwater lair, bound to eternal servitude. These spectral slaves
maintain the vodyanoy's realm, act as sentries, and serve as a source of unholy nourishment, allowing the vodyanoy to heal from even the most grievous wounds, ensuring that it can never truly die."