Regarding the animal names:
It has already been established in AtLA, regarding the Earth King's bear, that the base animals may exist but they are less well known than the mix-and-match critters in that world. You are right in that it doesn't make sense, but in this case your ire should be directed towards the AtLA creators for this and not the fanfic author. The fic author might be called to task for rehashing a gag that was done in the show once to hang a lampshade on the issue you just raised, but I'm of the opinion that it was still funny anyway.
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No, I don't believe the world has gone mad. In order for it to go mad it would need to have been sane at some point.
It has already been established in AtLA, regarding the Earth King's bear, that the base animals may exist but they are less well known than the mix-and-match critters in that world. You are right in that it doesn't make sense, but in this case your ire should be directed towards the AtLA creators for this and not the fanfic author. The fic author might be called to task for rehashing a gag that was done in the show once to hang a lampshade on the issue you just raised, but I'm of the opinion that it was still funny anyway.
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No, I don't believe the world has gone mad. In order for it to go mad it would need to have been sane at some point.