Hippomaritimus

Notes:

 * Found at the Siren Sands beach (H/I-9).
 * Spawns every 70-95 minutes.
 * Seems to have its own spawn, no placeholder kills necessary.
 * Seems inmune to Sleep, Sleep II, Bind, Repose and Gravity
 * Blind, Poison, Bio, Paralyze, and Slow work on it.
 * DoT's will stick to it.
 * Will use Intimidate (Pugil) and Screwdriver.
 * Aggressive to a Lv.59 job. Not aggressive to a Lv. 61 job. (Inaccurate. Didn't aggro to 24DRG or 55RDM)
 * Incredibly fast TP regain - One attack with staff was enough to trigger Screwdriver/Intimidate. -I've found that it has an average tp build. I've soloed easily with both mnk/whm73 mnk/war73 and dnc/nin63 even with Subtle Blow I would guess it has a normal tp regain and an easy solo for any 60+ DD jobs.
 * Can hit a SAM 75 for around 250 with Screwdriver.
 * Can hit a THF 50 for around 600 with Screwdriver.
 * Can hit a PLD 61 for around 150 with Screwdriver!
 * I soloed it at PLD/WAR 61, easy fight hit about 35 each hit!
 * Seemed to Screwdriver often, for about 270 damage on a well geared 65 SAM

Soloable by 55RDM/BLM (Hits hard and fast, keep up with your buffs! NIN sub would've made for *easy* battle). Intimidated often, used screwdriver twice.

Historical Background
"Hippo" refers to the Ancient Greek word for "horse", and "maritimus" can mean "of the sea" or "of the coast". Therefore, this monster's name means either "horse of the sea" or "horse of the coast", by interpretation.