You mean a wave?
No silly waves are on land. Have you ever heard of earth’s largest wave? Wave Everest. A lot of people climb it every year. Sometimes they call them land waves to distinguish them further from water mountains.
I know it’s really hard to tell, especially with flat earthers, but I think this post by “gerwin” screenshat here (with extra jpeg) was satire.
There are a lot of silly explanations that flat earthers have for things, but this doesn’t appear to be one of them.
(Googling for “water mountain” just gives this screenshot and people making fun of this screenshot.)
I’m stealing that word now “scteenshat” works well in this context
These people are so dumb, they aren’t “water mountains”, they are Lands with the subtypes Island and Mountain, meaning they can tap for blue or red mana.
the existence of water mountains implies the existence of forest, fire, shadow and spirit mountains
What are tides, but the water mountain reaching land. The ships disappear after passing tomorrow’s tide.
That’s why the Nazis went to the moon? So they could control the water mountains!