No chance of borrowing from vehicle code to make a long multi-tile monster, is there? Even two tiles would be novel. I know this is asking a lot. I also know vehicles aren’t how I remember. Moving as a solid block at strange angles as if it had no ability to bend would not be out of place anyhow.
I want a nether creature that moves like a long, god-damn train of limbs. I want neatly spaced, repeated legs the whole way down like a caterpillar with limbs somewhere between a salamander and a human’s arm. Eyes or other features repeating like they were determined by mathematics, fading in at the front and fading out in the back like a looping gif. It is non-hostile, but it moves fast enough that if you are in its path, it might not turn out of the way in time.
I want it to shimmer like the nether portal it tore through at fullspeed. Like when you look at a blacklight and you get that visual fuzzyness from it but you can’t see ultraviolet. (please tell me everybody thinks blacklight “light” looks like a fuzzy “impression” of light.)
I want it to suck the warmth out of whatever tiles it crosses, feeding not by mouth but directly through the absorption of energy. I want a massive Fuck-You to the eventual heat death of the universe, on hand-legs, leaving trails of horrid cold like the deepest layers of ice labs. It fades in time, but passing through the cold would incur the usual penalties much like standing too near a fire’s heat does.
It is neither hostile nor friendly, it is a force. You don’t reason with it.