Being a bit of a closet Biology nerd, when you see a design that combines love of folding with something biologically interesting you jump at the chance to fold it:

This modular is made up of a bunch of bent arrow-shaped modules that slip together in 2 strands that then, rather satisfyingly, intertwine in much the same way as worms do when they are mating.

…slight mistake with the scale, should have folded them out of 3 or 7cm squares instead of 15, but hey.