The digital animated images in Watching Europa are not made in the same way as those that you may be accustomed to seeing in the movies. My underwater world is not modelled in 3D and then given transparency and texture through purpose-built descriptors designed especially to emulate water or light. The Europan creatures, likewise, are not built with digital modelling tools that are specifically purposed for imitating real things like jellyfish, or leaves or tentacles.
My canvas is, instead, simply a Cartesian Plane, and all the properties of the world I have made are illusions that arise from interactions of reasonably simple mathematical descriptions. It is true that I have a great deal of control over those descriptions, but an important aspect of my work is to allow a sort of 'wildness' to creep in, in order that an amount of genuine surprise informs the process.
This is possible through a powerful and somewhat counter-intuitive notion: that of non-linearity and complexity. To put it very simply, I can describe some very simple rules for a part of the Europan world but because of the vast number of interactions in my mathematical systems, it is impossible for me (or anyone) to know exactly how those interactions will play out. Not only that, but looking at the end result of those interactions will not allow you to deduce what rules were in play or what they were doing - no matter how simple those rules were.
Of course, complete unfettered randomness would result in total anarchy so I apply some strict conditions to exactly what I allow to 'go wild', and I avoid having rules that I know will destroy the system. Even so, there is enormous novelty available to me, and the methodical exploration of that novelty results in Europan creatures that often surprise and delight me, as I hope would be the reaction if we found real life on Europa.
In a very tangible way, the lifeforms you see in Watching Europa are following similar rule systems to those that probably define actual life. The major difference is that the parameters of my fictional Europan world are established by my input, and the natural world has its constraints imposed by evolution.