Creature type (Dungeons & Dragons) animals despite their real-world bases being more closely related to vermin type creatures. Creatures deemed inconsequential by DMs or designers are not given any creature type at all, instead being treated as "set dressing" unless a specific game effect targets such non-creatures. Examples include actual-sized spiders, sparrows, fleas, worms, shellfish, and mice. "Swarm" type creatures are occasionally written to represent such otherwise nonthreatening creatures if they were to group together by some force of magic within the game world. Under the rules of D&D, animal type creatures do not have an Intelligence score higher than 2. When a designer makes
Blood type (non-human) a horse or determining parentage. Unlike humans, horses do not naturally produce antibodies against red blood cell antigens that they do not possess; this only occurs if they are somehow exposed to a different blood type, such as through blood transfusion of transplacental hemorrhage during parturition. Breeding a mare to a stallion with a different blood type, usually Aa or Qa blood, risks neonatal isoerythrolysis if the foal inherits the blood type of the stallion. This can also occur if a mare is bred to a jack, due to donkey factor. This immune-mediated disease is life-threatening and often requires transfusion.