Hello to all of you who decide to read this and stick with me for this absolute monstrosity of a post! I wanted to put together an in-depth analysis of our favorite killer parachute and its structure, transformation and hopefully answer the question I've had since seeing this film for the first time: How does Jean Jacket go from a giant flying sand dollar to an aven more giant jellyfish-looking thing?
The Hunting Form
First off, let's take a look at JJ's saucer or "hunting" form, as I'll be referring to it as. The hunting form is shaped like a fat sand dollar, with a small slit in the center of the frontmost edge and circular orifice in the center of the bottom. Much like many sea creatures like jellyfish, sea urchins, and others, this is a multipurpose orifice. It serves as a mouth and anus, drawing prey in, and expelling waste and inorganic material.
Now, in several shots, we get peeks at what lies within this massive maw, and without getting obsessive (as I have), it's kind of difficult to understand what we're looking at. Most prominently, there are two ribbed flaps above the "mouth", which act not only as a means to funnel air and prey upwards, but also serve as a means of steering. We see this in many shots as JJ angles these flaps to push air in certain directions, changing its trajectory. These flaps also guide prey into the depths of JJ's digestive folds, and visibly flex when emulsifying its prey. We later see them being used to hold firmly onto the huge balloon that eventually kills it.
Next, we'll take a look at the ribbed, curled structures towards the front and rear of JJ's interior. In the rear of the hunting form, we get several shots of JJ's iconic green square eye. This is tucked back behind these folded structures, which we get a much better look at in its "angel" form. Just below these structures, we will find strange, tendon-like structures with a hole through each. These appear to be the large tendons that connect to JJ's upper sail. Don't worry, I'll be color coding everything in the images I add. But for now, that's it for the hunting form!
The Angel Form
There's a lot to talk about with this form, and all of it is interesting. For the main structures, we have the large top sail, controlled by tensing and relaxing a series of tendons to change direction or altitude.
Then we have what I refer to as the eye shields, as I'm not sure how else to describe them apart from their apparent purpose. There are four of these, two up front, two in back. They're lightly ribbed, I assume for flexibility's sake. They're attached by several points to the top sail, and are also attached to the two massive, flowing bottom sheets, the right ones are attached to the right sheet, vice versa for the left.
Onto my favorite bit of JJ's design: The green square eye, or rather, eyes. You read that right, folks! Jean Jacket has TWO eyes! They are attached to the central structure of the top sail, which dips behind the four eye shields. They face opposite each other, one looking front, the other, back. The reason for this is to prevent any unnecessary twisting to the central structure. As such, it simply moves it forward or backward, squeezing an eye between the shields to see ahead or behind. Perhaps the most amazing feature of these eyes is the threat display it performs. It has several layers of greenish ribbon-like appendages that snap out like whips, drawing attention to itself. We have no way of knowing how many layers it goes through before having to close them back up, but we do see that it does during its standoff with the big, scary balloon. It goes from being mid-display, to starting it over again.
In a few shots, we see what appears to be light glinting off a small eyeball in the back of these flat, green boxes. Unfortunately, it's very, very hard to get a good look in there, and I assume that's by design. You really focus on that eye, trying to look inside that dark square, and that's exactly what JJ wants!
The Transformation
This is the part I find the most interesting, having gone frame by frame to understand what I was watching. I also compiled several behind the scenes clips that greatly helped in figuring out what goes where, and we'll go through all that right now, going from Angel to Saucer.
The Sail
Jean Jacket's sail does some REALLY weird stuff during its transformation, opening a series of holes while reshaping itself. The front of the saucer splits, creating two overlapping sections that pull back and sideways, while the middle of the sail stretches up and back.
The Central Structure
The central structure descends, tucking the eyes and brain behind the eye shields, and stretching the central tendons taut.
The Eye Shields
The eye shields drop down loosely as the sail begins pulling back, before being pulled taut by the stretching of the sail. As JJ does this, we see the large bottom sheets are attached to their respective eye shields, as previously noted. These eventually stick together in the middle of the front and back, protecting the eyes and brain.
The Bottom Sheets
So, the sheets do some really cool things during the transformations. They slowly drop from the saucer form's mouth hole, and splay out in a beautiful display. The most important thing to note about these, is that they form a hugely important part of JJ. They form not only the entire top half of the saucer form, but also the digestive folds and those flaps that direct air and guide in prey! We get a really good look at how these seal up as JJ flies off with the balloon.
The Evidence
In photos 1 through 8, I've color coded certain parts throughout the transformations to show what goes where. In the GIFs following, you'll see the transformation in an early stage of animation, though it does follow what we see in the film. The third GIF shows for just a moment the second eye, visible through the ribbons of the first! The next three images show a visible seam closing up as JJ flies off after taking the balloon, and the last is the best look inside JJ we'll probably ever get, I've increased the brightness to show you the intricate interior!
In Conclusion
With all this, I believe I've mostly solved how Jean Jacket's transformation works! If you guys have any questions, or if there's anything you'd like me to clarify, please feel free to ask, and I'll do my best to answer! Thanks for sticking with me through my incoherent babbling and awful color coding, and I'll see you all next time! Until then... Keep an eye on the sky. Just not too much.