Complementary Nautilus

Have you ever looked at the nautilus shell from vanilla Minecraft and felt like something is missing? A nautilus is a cephalopod with a spiral shell considered to be a "living fossil" more closely related to early cephalopods than other modern species.

Features:

- The purpose of this mod is very straightforward: to add a nautilus mob to complement the item. - They will spawn rarely in any biome specified by the tag: `data/nautilus/tags/worldgen/biome/spawns_nautilus.json` - By default, this will be the ocean, lukewarm ocean, deep ocean, and deep lukewarm ocean biomes. - They drop exactly one nautilus shell. - The swimming motion is based on that of fish, but slightly faster to escape players. - Out of water, they will fall over onto their side.

I know the nautilus shell is supposed to be a rare item for crafting a conduit or trading for a trident. However, some players might find it too uncommon.