Happy War Machine

What is it?
A WM in the flyer room or above in OOB. Specifics on this Glitch are missing, in the video below it shows a WM flipping around several times at one place, it floating in the flyer room, tail shaking etc. It also says it can shake its head sometimes.

Short describtion of the glitch, a longer video and text on how to get it should be added.

How and where to do it
Level: Underground