I just thought about an even better example of "incredibly scary real animal but its pokemon version is adorable"... Lanturn. As you know, Lanturn is based on an anglerfish. Not only are the female ones not cute at all in real life -though the male ones are actually much smaller and nowhere near as scary as the fameles- but they employ a rather... disturbing method of reproduction.
From Wikipedia: At birth, male ceratioids are already equipped with extremely well-developed olfactory organs that detect scents in the water. The male ceratioid lives solely to find and mate with a female. They are significantly smaller than a female angler fish, and may have trouble finding food in the deep sea. Furthermore, the growth of the alimentary canals of some males becomes stunted, preventing them from feeding. These features necessitate his quickly finding a female anglerfish to prevent death. The sensitive olfactory organs help the male to detect the pheromones that signal the proximity of a female anglerfish. When he finds a female, he bites into her skin, and releases an enzyme that digests the skin of his mouth and her body, fusing the pair down to the blood-vessel level. The male becomes dependent on the female host for survival, receiving nutrients via their shared circulatory system, and provides sperm to the female in return. This extreme sexual dimorphism ensures that, when the female is ready to spawn, she has a mate immediately available. Multiple males can be incorporated into a single individual female.
Back on topic, a tarantula hawk pokemon would be a perfect candidate for a bug/dark-type with high attack and speed.