My friend and I fought Plesioth yesterday and I think I have decided upon my least favorite enemy. >_> I thought I disliked its land-dwelling cousin but my friend wasn't kidding when he said the water variant was worse.
You had to literally dive into the water to fight it off there (along with all the other underwater enemies) in MH3U. @_@
Granted Plesioth in particular doesn't really move around too much in the water but depth perception goes to hell down in that place.