This is a really cool creature from the Rime of the Frostmaiden adventure for D&D 5E! It was inspired by the iconic poster for 1982 version of The Thing:
I love that movie, so I really appreciate the homage! Coldlight walkers are the reanimated corpses of humanoids who died from cold exposure. Awesome! Really makes me want to run this adventure, just to have players encounter this creature!
I hope you all have a safe and fun Halloween!