The stronger variants have large yellow coral growing on one of their eyes and smaller coral patches on their ribcage and legs. They are seen holding an Elite Power Bow.

Behavior:

Like their normal counterparts, they attack the player via ranged harpoons that can travel underwater and have greater health due to the heavy coral growth.

More Info: https://minecraft.fandom.com/wiki/Minecraft_Dungeons:Armored_Sunken_Skeleton