D&D Monsters: Remorhaz(es)

The remorhaz is another creature original to D&D, and one of the few such that is honoured with a proper name rather than a descriptive term. It's one of the more powerful creatures in the 1st edition that are described as simply animals, rather than intelligent beings. This is largely because it's so difficult to hurt, although it also has a bite that does more damage than that of most dragons. In later editions, it's toned down, although it remains quite fearsome.

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1E

As originally depicted in the 1E Monster Manual, the remorhaz has a snake-like body, with a thick leathery hide that's harder to penetrate than plate steel. The upper surface of the body is covered with an irregular array of white protuberances, which apparently shed excess heat from the intestines. The lower surface has a series of wide flat scales, which also resemble those seen on many snakes, reinforcing the resemblance. The key difference, of course, is that the remorhaz also has a huge number of legs. These are multi-jointed and covered with an exoskeleton; the segments within the leg are all of similar size, suggesting the relatively simple structure of a centipede's legs rather than those of a spider or insect. 

D&D Monsters: Cloud and Storm Giants

Cloud and storm giants are the most powerful of the standard races of giant in the D&D rules, the two final rungs on the ladder of increasing humanoid power. There doesn't seem to be any specific inspiration for them, although giants are sometimes associated with the sky in myths and legends. They are also the most intelligent, and the most inclined to be helpful, rather than hostile.

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1E

Cloud giants are 18 feet (5.5 metres) tall, with bluish skin, and, unlike other giants, have what appear to be blunt, but greatly enlarged, canine teeth in the upper jaw. They aren't shown or described as wearing armour, so their skin must be equivalent to plate steel to explain their stated armour value. Most are of regular human intelligence (which is still smarter than most of the smaller giants), but a few are slightly better, and have limited skills with magic. They are said to have a particularly keen sense of smell, which is likely a nod to the cloud-dwelling giant in Jack and the Beanstalk, although they are otherwise quite different. They are also the first giants tall enough to have a stride that enables them to walk faster than humans, although still less than one might expect, given that they're about six times taller than we are.