young dragon
虯 refers to a young dragon, a mythical creature often depicted with horns and a serpentine body.
虯 combines 虫 (insect/reptile) with 丩, which likely contributes a phonetic element. The character is used for a type of dragon, but the exact historical development is uncertain.
The left side 虫 suggests a scaly, snake-like creature, while the right side 丩 looks like twisting horns. Together they form a young dragon with horns.
For キュウ, imagine a cute young dragon named Kyu: Kyu -> キュウ, and the little dragon curls around the 虫 and 丩 parts.