The mystery of the Archaeotania FATE.

This big nasty seems to spawn in the final "hidden" zone of Shadowbringers and drops the horns needed for the coveted frog suit glam.

There's a chain of FATEs pertaining to it that involve helping an Ondo hunt it down, but after seeing said chain get completed three times in the course of a few hours, the boss FATE never showed.

It's possible it might just have an invisible timer like Foxy Lady, but the fact that I haven't seen a single reported spawn since launch makes me feel like there's some kind of other requirement that's being overlooked.

One of the level 80 dungeon quests does pertain to attempting to get information about it, so perhaps it simply can't spawn unless a player who's completed said quest participates in the last FATE?

We saw this pop earlier today. Kholusia - 1st is its hidden FATE (similar to Odin), someone must physically get within range. 2nd - All attempting were 78 or lower, big butt whooping very quickly. TONS of HP.

Position is (sorry no coordinates) north side of wall, east of river, NW of a south side aethercurrent; due South of a north side aethercurrent. There is an extension (nipple) feature of in map similar to lower half of Africa. Physical appearance similar to boss in A4 (we died quick-not real good look).

The Kholusia one gives cogs for the frog robot mount, the OP is referring to the one in the final zone that gives horns for frog suit

Here is the list of fates in the chain from the reddit thread: https://www.reddit.com/r/ffxiv/comme..._achievements/

1st Fate "Where Has The Dagon" NPC Teushs Ooan spawns at (23.2, 22.7). Soon after that,
2nd Fate "Ondo of Blood" NPC triggerman appears at (28.9, 12.6). Shortly the
3rd Fate "Lookin' Back on the Track" NPC triggerman spawns at (24.2, 17.9). Protect the NPC. Next, the
4th Fate "Coral Support" spawns by talking to NPC at (35.3, 9.5). Escort Fate. Right after, the
5th Fate "Low Coral Fiber" NPC triggerman appears at same location. Delivery Fate
Now it can loop back to start of fate chain, or onto 6th fate.
6th Fate " Nothing Like a Trappin' Life" at (26.9, 24.7). This fate does show on map, and needs flying to access area.
7th Fate "The Head, the Tail, the Whole Damned Thing" at (27.1, 26.5). DOES NOT SHOW ON MAP, and NEEDS flying to access area.

The NPC you are looking for is Teushs Ooan. There is definitely a hidden timer that determines whether the fate can continue from 5 to 6 or if it is going to just loop back to 1.

We saw it pop already on Spriggan (I wasn't online unfortunately). A member of my FC farmed it for three days on and off and the chain kept breaking. So we are assuming that there is a hidden timer.