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LOL, was that a rathian going under water?

Kindy look like a Kut-ku

looks like a yahn garoga (black kut ku) or a rathian

It's a Rathian, I have yet to see a mission where you fight a Rathalos in the jungle. Not only that but you can tell just by looking the wings.

http://www.youtube.com/watch?v=OQB4hbHsA6k&watch_response

Yes, that is possible, and still happens even in Freedom.

it happens when a glitch in the game occurs, unknown glitch to that matter, it causes the AI system to become confused, and force make a new landing path off the spur of the moment. Hence, its landing place happened to be the water.

And the lava 'glitch' isn't really a glitch, the only reason any animal in the Volcano area that has Lava there, is because the Gravios is unaffected by lava, the programmers had to make the lava unable to hurt what you fought for the simple reason being, if it hurt the Gravios, it would have to hurt everything else.

The Kut-Ku does some weird things...

I think i know what happened. Is this an incident which mirrors rathalos. whenever u fight rathalos in the forest&hills and he flies at u in area 5 i believe, he may sometimes fall over the edge. this might have happen except she fell into the water