most animals that start adapting to live more of their lives in water:

"i must grow my bones lighter and less dense so that i don't get trapped on the bottom and may float easier in this new environment"

hippos:
"denser. heavier bones. MOAR dense. Make sink the most."

mother nature:
but how will you get off the bottom when you sink?

hippos:
Make muscles more too, give all muscle.

mother nature:
and to stay warm in the water? a big layer of fat?

hippos:
no! no fat only muscle.

mother nature:
o....kay. And, you eat aquatic plants, that's why you spend so much time in the water?

hippos:
lol no. eat land grass, like cow.

mother nature:
i see. right. You eat mostly grass, so, flat grinding teeth?

hippos:
hell no. big spike teeth. sharp big teeth. Biggest

mother nature:
what, like lions? 3 inch fangs?

hippos:
course not. giant fuck-off teeth, 18 inches. Also, not just one pair, three pairs of giant sharp teeth. give

mother nature:
but you eat... grass?

hippos:
yeah. lol. Sometimes eat a zebra tho. Or a antelope. Maybe eat a crocodile, you don't know. Give all teeth, giant fuck-off teeth. Most bone! most muscle! most teeth! Me.

mother nature:
y'know what? fuck it, sure, here you go

hippo:
...

hippo:
i'm very angry now

so idk about layers, and they are not all the same size, but they have three pairs of large sharp teeth on each side of their mouth, or you could say six pairs of ...? anyway they have a bunch of molars you can barely see through the gums, and then they have these teeth:

looks like this in the mouth

so those are their, yeah i guess actually six pair of giant fuck-off teeth

You ever see a post that just looks like someone swinging an incredibly high resolution bat at an impossibly busty hornet’s nest?