Journey (PS4).
Soulfly helped me witness this when they went to trigger the WM from below. VERY neat! I'll see if ID rule matters next time and also check if my equations are right below.
This is the Bat Form (Tail up, head down, flips head only) and I need to retest this next time but it might be this generally speaking:
(Solo)
Activate Ambush WM+WM1 Spawn Trigger in Z Corridor = Bat Form in Southeast # outer wall.
(With Companion)
OOB via Jelly Room + Wind/Camera Trigger at Shrine+ Go back into OOB + Have Companion Sit on Wall (where I am in the video) + WM1 Act + Rescuing flyers = Happy War Machine (Bat form)
Need more tests but I think both players can see this regardless of ID rule?
When Soulfly was HID and I was LID, Soulfly was able to make WM1 do Head Flips twice by going backwards in the level to the Ambush Room ....and this recording actually is from the second attempt.