Prometheus introduced us to a new set of monstrous creatures, each with its own physiology but visually linked to HR Giger's original Alien designs. Concept artist Ivan Manzella has released several of his concept designs for the beings we meet on LV-223. Major spoilers!
Manzella worked with Neal Scanlan studio in developing the concept designs for the creatures born from the Engineer's goop. His images give us a better look at their biology, which in some cases is truly disturbing. He has even more images of Prometheus' biological horrors on his website.
S S SMedapod Creature
S S STrilobite
S S SWorms
SAnd this critter...