Here’s an alternate idea for what kelpies could be (shapeshifting fairy crocodiles that mimic the appearance of horses) from one of my favorite non-pony artists.

@Background Pony #3C32  
Eh, Wendigo i’d put down as worse since all you really need to do to avoid a kelpy is not pet it or get on it, while a wendigo will actively hunt you.

DOES ANYONE ON THIS SITE KNOW WTF a Kelpie is because it’s almost as bad as the wendigo

@RIG
 
the sirens from rainbow rocks look pretty nice too.

So…another species…?
 
And WHAT ARE THEY? KELPIE? Then what about that one (Cassie’s design) in FiM#23?
 
The official has made a consistency modification to the species (mermare)’ design. But this time…?
 
Or Cassie’s design is “demonization (or something like this)” of these “Kelpie”, like Siren-Pony and Siren-Monster?

Marisprites?

@Darth Sonic  
Also, the way Cassie was singing to hypnotize everypony in town to do… whatever… is really more suggestive of a Siren than a Kelpie. I prefer to think of kelpies as amphibious, carnivorous, horse-shaped creatures native to inland freshwater environments (4 legs, gills, sharp teeth, slimy skin, maybe a shark-like tail, kelp in their manes, etc).

@PonyPon  
Could’ve migrated there, but the coloration honestly doesn’t really suggest something native to shallow waters.

@Darth Sonic  
their hmmm, maybe the comic came out before that design was shown up. the comics are not all done in order of release after all.

@Wyvrex21  
Wasn’t it living in a lake or river?

@Align  
Personally, my headcanon for the Ponyverse’s equivalent of Atlantis would be “Antlertis,” an ancient deerfolk city that sank beneath the waves after being ravaged by vicious Perytons (thus tying in the mythological association between Perytons and Atlantis that exists IRL).

@Darth Sonic  
A deep-sea sub-species perhaps?

If these are Kelpie, then what the Hell is this?
 

@Align  
Agreed. I believe the name “Kumarei Kanter” (after the mythical sunken city of Kumari Kandem from Hindu mythology) would be a much more clever pun-based name for the hippocampus capital. Unfortunately, most people don’t really KNOW about Kumari Kandem, so the joke would be lost on the general public and they end up going with the overused “Atlantis” pun (and though it’s more original than the usual “Marelantis,” it could have been better if it were instead “Shetlantis”). However, I do rather much like the fact that the underwater city appears to be made from living coral.
 
 
@Background Pony #C77E  
Nah, Sirens are WAAAAAAAAY uglier, more horse-faced than pony-faced. Those are clearly hippocampi (a name and design I personally prefer far more compared to either the mermares or the seaponies). Also, the merfolk city from “the Little Mermaid” was called “Atlantica” (after the Atlantic Ocean… which I never noticed until just right now had such a similar name to Atlantis).

@Background Pony #162C  
make matters worse those would be sirens, technically……….
 
mermares and keplies have no limbs, but sirens do…….  
this whole story is nothing but a continuity issue!!!! also it is a reference to atlantis and the little mermaid if you didn’t notice.

>Coltlantis  
laaaaaame

this page was so weird for me. they dedicated an entire full page to just this long shot of coltlantis and then never went anywhere with it. i mean i guess its pretty enough…but it doesnt blow me away as a spectacular vista that deserved its own page with no follow up.
 
was the artist like ‘im gonna put my kelpie fanfiction OCs into this comic and theyre gonna have an entire page dammit’?

@RIG  
Because they were maremeids

me: Yo, Sebastian! Get over here and sing the song that fits this page!  
Sebastian: You got it, mon! sings Under The Sea

Finally, g4 sea ponies that doesn’t look ugly, unlike those ones from the pirate arc.