Just because the sun came out that doesn't mean everything's better. Giant Mountain Satan is till there. LURKING IN THE DARKNESS.

In Fantasia, the conductor dude actually explains the reasoning behind using "Rites of Spring" - it's paired with the amoebas/dinosaurs because that was the springtime of the world! But you still have to wonder about the meeting where they came up with this idea. Indeed, every single meeting about Fantasia must have been fascinatingly bonkers.