The Meanest Savage Mechanic

[LalaRu]

When I hear the sound of "backfire".

Ho, wait…

[Dualgunner]

Kefka's tank buster Wings of Destruction makes me the most nervous even though executing it properly isn't that difficult at all.

Gotta answer this as well. One of my groups screwed this one up so hard for about a straight week that just hearing the effect makes me flinch even though both groups have done it flawlessly several times since.

[Daeriion_Aeradiir]

Meanest of all? Nisi when done properly at the gear level of the time.

Though it's ultimate, I think Exaflare is the meanest due to just how it comes 16 minutes into the fight and how unless you have some crazy dps, you need everyone to dodge all 4 sets perfectly or you die to enrage.
No other mechanic to date has gotten my heart pumping as much as anytime I enter Golden does purely because of Exa.

I will say though that I was never the biggest fan of Double Allagan field in T8S.

[Sebazy]

Gonna second Nisi in A4S and by a long long way. Doing that mechanically legitimately really is something to behold (And the number of teams that have done this make ultimate look mainstream).

Venemous Tail in T7S gets an honourable mention, for such a simple thing, that poison has snowballed a lot of runs.

[Berteaux_Braumegain]

My current least favorite is at the start of the final phase of a8s, regardless if synced or unsynced. It's been so long since I've been in there that I forgot what it's called, but basically you're trying to recoup from a big attack and there are things to do all over the damn screen, and people who are supposed to handle their specific spots are sometimes on the wrong side of the arena (or dead). Maybe my memory's a little fuzzy, but that mechanic makes my eye twitch just thinking about it.

You're thinking of Gavel.

[Ameela]

Meanest?

Probably the floor puzzle in O3S where Hali asks if you're failing it on purpose :^)

[RyuDragnier]

Meteors, specifically the T9 variety. There's a reason why I get bad flashbacks and start crying whenever somebody mentions that place.

[ImDingDing]

like players in the weekly clear PF or those clear for alt/friend i360 PF or clear for one then farm?

[Harukochi]

White Hole & AA

[JunseiKei]

T11's critical buff from the node, making the boss's next attack a 100% crit. Considering how easy it could be to make something like this pop up in a fight, coupled with how strict something would need to be done (like a force a boss to take this buff so it only affects a single target, mayhaps a tank buster and a tank can use awareness, versus an already hard hitting raid wide AoE because you killed/lured the add too slowly) makes this a completely terrifying mechanic in my opinion.