The Sea-Mares are the three small assistants of Posea Reef. They are humanoid seahorses with the traits of a different monster each. One's a vampire, the second a kraken, and the third a skeleton. They have their own language which sounds like indistinct chatter and which is visually backed up with bubbles displaying simple symbols to get the message across. They are shown to play pranks and fool around, like throwing a starfish at Posea Reef
All three have the same English voice actor, namely Cindy Robinson.
They're mischievous little creatures who help out Posea as much as they friendly mock her.
The sea-mares are water monsters with a sea horse like lower body and an upper body that has traits from other monsters while still looking somewhat human like. Sea-mares are also very small, one of the sea-mares has a dark blue like sea horse body, pale purple bat like fins and, other vampire like traits like fangs and point ears. Another sea-mare has a pale blue sea horse like lower body, having pale green hair with a streak, and tentacles on her back and curve of her sea horse lower half. And lastly the other sea-mare has a pink sea horse lower body and hair, but also has pale skin, and appears to have a lack of a nose much like skeletons lack of a nose.
There appearance is similar to a hybrids appearance being a combination of two different kinds of monsters in appearance. But the sea-mares have not been confimed to be hybrids.
- November 26, 2014: Mattel requests the trademark for Sea-Mares.
- Mid November, 2015: The Sea-Mares make their diary debut in Posea Reef's Great Scarrier Reef - Down Under Ghouls diary.
- February 01, 2016: Mattel abandons the trademark for Sea-Mares.
- February 12, 2016: The Sea-Mares make their 3D cartoon debut in "Great Scarrier Reef".
- The Sea-Mares were supposed to be released as toys along with the rest of the Great Scarrier Reef crowd. They were trademarked, Posea Reef's profile lists them as her BFFs which is something that only happens to characters with dolls released prior or concurrently, and they fit in the "doll collectibles" category of merchandise that Mattel launched with the Fright-Mares and has since continued with the Garden Ghouls - Winged Critters.