Tarkus_20K said:
Well, I thought that with the name "mr._skull" having more posts (119 pics) it was the first name. But it could be "ratatata74". So maybe ratatata74? over mr._skull?
Often what happens is users will make an account with one name, someone will add them to danbooru, then later they'll change their names, so we can either continue using the old name or alias it to their new name. Seems in this case someone wasn't aware they changed their name so they made the new artist (ratatatat74), which is why it's usually better to make the alias to the new name.