Acolnahuacatl

Notes:

 * Found at (F-10), timed pop every 2h exactly.
 * Uses only Chaotic Eye.
 * Hits extremely fast and hard. Caution is advised if you do not have Utsusemi.
 * Has a high rate of Double Attack.
 * Has Enstun effect on melee attacks (not 100%).
 * Immune to: Bind, Gravity, Repose, Sleep.
 * Has very low accuracy, so good evasion tank can kill it easily.
 * Is very easy to solo as 75Dnc/37Nin with loads of eva gear. Switching to Haste gear for shadows gives him a chance to chain-stun you but you can still manage for a short time.
 * Soloed by a 75SMN/37NIN using Garuda. Battle took 5 minutes using 5 Predator Claws averaging in 1500dmg.
 * Aggressive to a lvl 75

Historical Background
Acolnahuacatl (also referred to as Acolmiztli) was a god of Aztec Underworld. Acolmiztli, which means "strong feline" or "Arm of Puma" in Nahuatl, was represented as a black-colored puma, with a supernatural roar, who kept the living from passing into the kingdom of the dead.