I notice that in the Roadrunner episodes I've seen, there are three sky types. Some, like "Fast and Furry-Ous," have a regular Thulcandrian sky. Some, like "Stop, Look, and Hasten," have the very pale blue Malacandrian sky. And some, such as "Zoom and Bored," have a yellow Perelandrian sky.
Eudyptula albosignata