There's a twinkling tree in West Sarutabaruta. I think, never been able to find it again. Pretty sure it's involved in a quest.
In Jeuno, there's 5 HNMs outside Jeuno in both the immediate outside zone and the zone linking to it (skipping Pashow, oddly). Each of these are 21-24 hour respawn monsters. They're all the same level (50-55 in "HNM" levels). They all have insanely low drop rates. They're all also in pretty hard to reach places.
Out of these, Waraxe Beak stands out as an oddity. Four of the NMs drop useful items that relate to the abilities of the monster. King Arthro attacks fast and uses Hundred Fists. Roc uses Benediction. Simurgh has incredibly high evasion and uses Perfect Dodge. Lumber Jack uses Blood Weapon (and it drains on hit? maybe?).
Waraxe Beak, uhh.. Where does "rain" even come from? It never rains in M. Mountains, nor is he strong or weak against Water abilities. He doesn't cast them either. They're also incredibly weak gloves and they've been useless as far as I can remember. It's long been suspected that they're one of the items remaining with an undiscovered hidden effect.
Noble Mold is another interesting NM. People have thought they've figured it out for years, but there's evidence that conflicts just about anything. Is it correlated to the seasons? Probably. What else? Nobody really knows. It just takes way too much time to get it to spawn once, yet alone enough to properly test all of the variables.
The amount of mystery they've thrown into this game is insane. These are just the ones off the top of my head. There's something curious in just about every zone.
I actually have the answer to Waraxe Beak.
Back in 2010, I compiled all the info I had on the history of NMs in FFXI (when they were added and a little bit more) and did some further research- http://forums.ffxiclopedia.org/viewtopic.php?f=1&t=26148
Anyway, Roc, Simurgh, King Arthro, Lumber Jack as well as Behemoth were part of the first wave of HNMs added to the game, being added in the Sept 2002 update (yep, FFXI HNMs just celebrated their 10th anniversary). The 4 directional Shadows were added then too. The 7 Sin Skeletons were added in Nov 2002, Serket & Capricious Cassie in Dec 2002, rounding off FFXI Vanilla.
Some of the biggest surprises were the launch of Rise of the Zilart added a number of new NMs, some HNMs, to Original zones. I knew the huge HNM Rams were added then but didn't know until I looked into it Waraxe Beak was, Cemetery Cherry (KRT was expanded with RotZ, Bostanieux was greatly expanded), and Sea Horror. And Delkfutt's Tower was a rather empty place NM-wise before RotZ.
The relevant portion of that tome- - Yes, Waraxe Beak being from RotZ is a bit of a surprise. I found 2 references to Waraxe Beak in 5/03, none earlier. I should have noticed it wasn't on any 2002 NM list and the fact that it was one of the few seeming 1.0 NMs that could not be found with a "copyright 2002" pic, just "copyright 2002, 2003" pic (like all the Gigas NMs besides Mimas, like Sea Horror). The clue should have been the gear as well. Waraxe Beak drops Monsoon Tekko (effect in rainy weather). Sea Horror drops Monsoon Kyahan, Voll the Sharkfinned drops Monsoon Jinpachi, and Mouu the Waverider drops Monsoon Spear. All of them are from 4/03.
It's an oddity from new content being added to old zones and not exactly blending in seamlessly. The Nov 2009 NMs were far, FAR, worse in that regard though.
If you want to know many things about NMs you won't normally find on a wiki (well, historical backgrounds got added to their pages), it's probably in that topic. I also included some of the substance of what was in each update besides the NMs, as well as many oddities (like the Awd Goggie mystery, mysteries with Goliath, Glyryvilu, Yilbegan, trying to untangle Expeditionary Forces, et al) and singled out NMs that were highly overlooked. I gotta add everything since Sept 2010. Maybe I can add the history of magic spells, abilities, and traits too at some point. If you love FFXI history, hopefully you'll really enjoy reading this. There are such things as Sky actually not
being the 1st tiered NM pyramid in the game, the time the Avatars were treated like HNMs to hunt, what hand a hurricane had in issues surrounding Chains of Promathia's release, the story of the mysterious 32nd Zeni NM, which enemies disappeared from the game entirely, and more.
And some other points:
- IIRC, one of the signature crystals had no possible use due to not being involved in any crafting recipes that could make a signable item. I think it was the thunder signature crystal.
- How about the black sheep NM Peallaidh? It drops Nightmare Gloves, an item with no practical use.