How can I change the position of mob limbs? [duplicate]

Solution 1:

You can't, this feature isn't implemented yet, you can only remodel blocks and items: https://minecraft.gamepedia.com/Model (archive)

Instead, you can remodel a block and use a falling_block entity. I honestly have no idea how custom models work, but there are tutorials online. You can apply it to this case for example like this:

/summon falling_block ~ ~ ~ {Time:1,NoAI:1,NoGravity:1,BlockState:{Name:"stone"}}

Of course you'll want to use something that doesn't appear anywhere else normally. If you can't guarantee that, you'll have to try to use items and the custom_model_data NBT tag. I think that applies model files like "stone5.json".