Ice-Crawler is a bug-like quadrupedalien. They are two meters (6'6ft) long that resemble pillbugs, are nearly motionless and make comically flatulent noises when emerging from their "sleep sacs". They inhabit the tundra regions of Darwin IV.

Unless seen from below, Ice-Crawlers show no signs of visible legs or even head, as their whole body is protected by a thick, jointed carapace. A view from below reveals a mouth and four stumpy paws. Ice-Crawlers move at a speed of about 35 kilometers (21 miles) per hour, which is amazingly fast for a crawling animal. As they move they shave the ice with their mouths, swallowing any frozen microorganisms and other nutrients, and leaving a very slick trail behind them. They go towards the areas where the ice is covered by colonies of tiny brown algae, as it provides them with a rich food source.